Yiffberries (inspired by Boinkberries, originally created by Richard Katellis)
What are they: A Kapernia-native berry that is used for contraception.
What they look like: Round burgundy-colored berries with multiple red bumps on them.
Flavor: Semi-sweet (comparable to raspberries)
Toxicity: None (in small doses), Mild to Moderate (in large doses)
How they work: The berries contain chemicals that, upon ingestion, work on the female reproductive system, temporarily blocking the hormones that stimulate ovulation during sex.  The effects of the yiffberries usually last about 48 hours once they have taken effect.
How they are taken: Can be eaten directly from the bush but are often packaged in medicine bottles after being freeze dried or being converted into juice form and turned into gel caps or candies.  Yiffberry juice is mixed in with cherry flavoring to make the candies.
Known side-effects: Males do not have the hormones that females produce to stimulate ovulation, so these have no effect on them.  Although, consuming large enough doses of yiffberries can cause stomach/intestinal discomfort.  Additionally, large doses in females can cause sterility if taken long-term.
Effectiveness: Greater than 99.9% (when taken at least 1 hour before sexual intercourse)
Risk to unborn children: Unknown (there have been no recorded cases of any abnormalities caused by yiffberries to unborn children, but that may be because females tend to not take the berries while pregnant).
Note: Before a female can begin to take yiffberries, an assessment of her potential fertility is needed.  Because of this, a doctor's visit is needed before she can start taking berries.

Kaorin Berries (from Drawn To Life, originally created by 5th Cell)
What are they: A berry native to Raposians that was brought from their home world to Kapernia.  Most of these are found on Raposa Island (part of the Arena Islands) and in groves in the town of Familia.
What they look like: Round golfball-sized berries with various colors (the color of the berries determines their medicinal properties).  Of the different types of Kaorin berries, only the pink and sky-blue berries are used for sexual purposes.
Flavor: Bittersweet (pink berries are slightly more bitter than sky blue berries)
Toxicity: Mild to Moderate (least toxic to Raposians, most toxic to humans)
How they work (pink berries): Pink kaorin berries work similarly to yiffberries, only they are more powerful than yiffberries are.  One pink kaorin berry is approximately equal to 2 yiffberries.
How they work (sky blue berries): Unlike the pink berries, the sky-blue berries act as a fertility booster, stimulating ovulation in females (and/or increasing egg production if a female is already receptive).  In addition, males can also eat sky blue berries, which enhance sperm and semen production.
How they are taken: Kaorin berries are usually freeze-dried and put into medicine bottles, though Raposians may also eat them straight from the bush.
Known side-effects (pink berries): Similar to yiffberries, though the intensity of intestinal/stomach discomfort varies depending on gender and race.  Human males are most at risk for developing digestive problems...perhaps serious enough to warrant hospitalization in large doses.
Known side-effects (sky blue berries): Can cause digestive issues in large doses (especially for humans), but not as severe as the pink berries.  In human males, constantly eating blue berries will permanently increase sperm production, causing the testicles to swell to as much as 2 times their normal size.  Males may also be capable of multiple orgasms with one erection.  In receptive females, egg production is usually doubled, and long-term use of blue berries can make this permanent.  Additionally (in human females), long term use of blue berries may cause shorter menstrual cycles, leading to more frequent ovulation.
Effectiveness (pink berries in females): Greater than 99.9% (when taken at least 1 hour before sexual intercourse)
Effectiveness (blue berries in females): Varies, depending on race and receptivity prior to taking the berries.  In most cases, for a non-receptive female, ovulation is usually triggered within 12 to 24 hours of taking blue berries.  Receptive females usually experience ovulation much sooner than this.
Effectiveness (blue berries in males): Varies, depending on race...males with high potency (rabbits, mice, Raposians, etc.) tend to have the strongest effect from the berries, often increasing their sperm production by 3 to 4 times within a couple hours after eating the berries.  Males with lower potency (human males, for example) take longer to respond and need to be on a kaorin berry regimen to experience significant increases in sperm production.
Risk to unborn children (pink berries): Because of their higher toxicity, there is a risk of injury to a fetus during pregnancy if the berries are ingested, though no known cases have been reported.
Risk to unborn children (sky blue berries): Minimal...although it is entirely possible for a pregnant female to ovulate again while already pregnant if she eats these berries!
Note: Only Raposian doctors (or doctors trained in Raposian medicine) are allowed to prescribe kaorin berries.

Flex-Mesh Condoms (my own creation)
What are they: Condoms designed exclusively for canid Kapernian races; regular latex condoms do not work for canid Kapernians due to their knot.
What they look like: Similar to regular latex condoms, only with a tip designed with the canid male anatomy in mind and also made of a more flexible/durable material, allowing the knot to grow without ripping the condom.  These condoms come in various sizes for all different types of canid males and are also available in many different lengths.  Some condoms also come with spermicidal lubricant to further increase contraceptive properties.
Available lengths: Normal (for penises up to 7 inches in length and a maximum knot size of 2.5 inches), Long (for penises between 7 and 10 inches in length and a maximum knot size of up to 3 inches), Extra Long (for penises between 10 and 14 inches in length and a maximum knot size of up to 4 inches), "Super Flex" (custom-made for males with penises of extreme lengths (more than 14") and a maximum knot size of up to 4 inches)
Available variations: Flavored (condoms that are designed with special flavors for oral sex.  These come in normal, long, and extra-long sizes), Big Knot (normal and long condoms that are designed to accommodate larger knots than the traditional flex-mesh condoms.  Up to 4 inches in diameter maximum size), "Cool Customer" (condoms designed for use when mating with fire-type canid pokemorphs.  Prevents burning of flesh of the male's partner), "Hot Dog" (condoms designed for use with ice-type canid pokemorphs.  Prevents freezing/frostbite during mating), Jumbo Knot (extra-long and super flex condoms designed to handle canid knots of up to 6 inches in diameter).
How they work: Similar to any other type of condom, the male places it over his penis before sex and then removes it afterward.
Known side-effects: None (all flex-mesh condoms are made of hypo-allergenic material)
Effectiveness: Greater than 99% (assuming the male uses the correct condom for his specific genitalia)

"Safe-Breeding Scrolls" (Originally created by Kitsuneyoukai...the way the scrolls work as described here may not be "in canon" with the way they work in Kit's "A New Life" comic)
What are they: Self-adhesive strips of magical paper with Japanese script written on them.  By placing a scroll on her belly around where her uterus would be, a female can be guaranteed that any offspring she produces will be born free of genetic birth defects or abnormalities...although the unborn children may still be susceptible to birth defects NOT caused by genetics (I.E.: Alcohol, Smoking, etc.).
What they look like: white strips of paper with Japanese scripture on them.
How they work: A female who wishes to breed must place a scroll on her belly shortly before she has sex with her partner.  It takes about 1 hour for the scroll to take full effect and each scroll gives the female up to 48 hours to conceive.  It should be noted that only egg cells released AFTER the scroll has been put in place will be protected, any egg cells released prior to usage will not be.
Known side-effects: None
Effectiveness (if used prior to ovulation): 100%...in most cases, see below for more information
Note: Safe-breeding scrolls are often used by incestuous couples, allowing them to inbreed without the risks associated with doing so.  While the scrolls are effective in preventing genetic defects in inbred offspring, there is a risk of failure of the scrolls if further inbreeding were to take place.  For example, if the daughter of an incestuous couple were to become pregnant after mating with another blood relative (even if she's using said scrolls), there is some chance that the scroll could fail to protect her offspring.  The risk only increases with each inbred generation, and this risk is also highest between siblings.

Uterine Caps (my own creation)
What are they: Synthetic flesh-like caps that are designed to block the entrances of a female's fallopian tubes.
What they look like: Flesh-colored balls that are inserted into the uterus by a doctor.  Once inside one of the tubes, a sealant is injected to make sure the caps are firmly in place.
How they work: The caps prevent sperm from entering the fallopian tubes and prevents egg cells from reaching the uterus.  The caps are semi-porous to absorb unfertilized eggs into the material, but each cap is laced with enzymes that will quickly destroy any gametes (male or female) that enter the cap.  Upon insertion, the caps are effective for 5 years (unless a female wishes to have them removed earlier).
Known Side-Effects: Very rarely, the enzymes contained within the cap will affect the tissue cells in the uterus and fallopian tubes, causing pain and a risk of sterility for that particular female.  Any female who experiences uterine pain after the caps are inserted will have to see a doctor for immediate removal of the caps to prevent further damage.  Genetic testing is recommended prior to cap insertion to ensure that it is safe to use uterine caps as an effective means of contraception.
Effectiveness: Greater than 99.9% (WARNING!: A handful of males are capable of producing sperm cells that are resistant to the killing enzymes contained within the cap.  Additional, improper insertion of the caps can also allow more sperm to reach the tubes.  If this occurs and fertilization takes place, there is a high risk for a potentially dangerous pregnancy.  It should also be noted that the effectiveness of the caps slowly decreases with time as the enzymes are either used up or become ineffective due to age (which is the main reason why the caps need to be replaced every 5 years).  Therefore, it is strongly advised that females use additional contraceptive measures while having the caps in place to further reduce the chances of this life-threatening scenario.)

Raposian Milk (once again inspired by the Raposa species, as created by 5th Cell)
What is it: The milk produced from a female Raposian's mammary glands.  Once a female Raposian becomes pregnant for the first time in her life, she will continue to produce milk for the remainder of her fertile life (usually early to mid-40's).  This is true even after she has weaned her sons and daughters off her milk.
What it looks like: Typical mammalian milk...white in color and slightly thicker than cow's milk.
Flavor: Sweet (flavor varies depending on the Raposian female and her diet, but most will produce either a "strawberry and cream"-flavored milk, or an "orange and cream"-flavored milk.  Other known flavors include vanilla-flavored and "banana and cream"-flavored.
How it works (in sexually mature males): Raposian milk to a sexually mature male acts similarly to sky blue kaorin berries...without the nasty side-effects.  Specific nutrients contained within the milk act inside the male's testicles, both accelerating sperm production and boosting their potency.  It is actually a more preferred method to boost a male's fertility than the kaorin berries because of this, though unless you're married to a lactating Raposian female it may be hard to come across.  Raposian milk has no effect on sexually mature females or for immature males/females, other than providing added nutrition.
How it is taken: It can either be taken in directly from a female's breast or packaged into bottles for refrigeration.  Drinking the milk from the breast is the best option, since it's both fresh and has the highest concentration of nutrients needed to boost sexual production (the effectiveness of bottled milk decreases with time).
Known side-effects: Because Raposian milk contains lactose (though less of it than cow's milk), those who are lactose-intolerant probably should not drink Raposian milk.  Also, long-term ingestion of Raposian milk will cause the same (positive) side-effects as sky blue kaorin berries...such as increased testicle size and sperm production, as well as the ability to have multiple orgasms with one erection.
Effectiveness: Varies (depending on the age and race of the male who drinks it).  Younger and more potent males will respond more to the milk than older and less potent males, although Raposian milk is about twice as effective as sky blue kaorin berries in increasing virility.