Little Irb Jr. tugged on your tail. "Please come watch! I want to show you a trick Uncle Con showed me!" He grinned proudly. "He said that us dolphgryphs are strong enough to swim in quicksand! I want to show you how long I can last!" He ran eagerly to the quicksand pool in the backyard.
He waited for you to follow, then he stepped back. He took a short running leap into the soft sand, splashing in waist deep. "Here I go! No ropes or anything!" He flopped forward onto his stomach and started to swim, every stroke of his webbed paws and strong tail propelling him through the smooth sand... but also working him deeper.
It didn't take long for his body to sink under, and then he was swimming properly, head poking up, webbed handpaws surfacing as he stroked along. He was swimming quite well in the thick sand, but he was also panting, and blushing. "I can last... much longer than Uncle Con can! He can't swim... at all! But it's tiring, and... distracting!"
He makes several laps before he's clearly tiring, and his panting is much louder. "Ahh... s-see? I'm a g...good swimmer! Just like you dad! I can... ahhhh..." He was slipping deeper, his swimming slowing down. He had to focus more on keeping afloat than making progress... but his swimming was rough and more like... humping, as he squirmed and moaned. "So... so soft and... cool... it's... ahh..."
Con Badger: Little Irl Jr. was soon just struggling to keep his beak up, panting heavily, moaning and panting. "I... I lasted... a l-long time... dad... see?" One of his webbed handpaws slipped down, as he also had a weakness for the sand's hunger. "Mrpgh..." Sand teased into his beak, and he sputtered. "G... gonna... drown now... but I'll practice and lrrblgh... last longblurglbub..." Only one webbed paw grabbed at the surface now as he sank under, the sand sloshing heavily where he humped it under the surface.
Then that webbed paw sank under too, and the sand sloshed harder, bubbles gurgling up noisily. He bucked and kicked and humped, moaning out his air in needy, lustful gurgles, as he pawed his way to a cubby orgasm. His squirming little body humped as hard as he could, his tail helping to push him about and thrust into the sand harder. He pawed himself to precum, but it was the desperate gasp for air... that filled his little lungs with the wet quicksand... that pushed him over the edge. You could tell when it happened - when the bubbles stopped, but the sand sloshed so much harder.
The little phingryph gasped and panted and wheezed, taking deep aching breaths of quicksand. Every breath filled his body with the pleasure-pain of drowning, and his little cock gushed cum into the sand, as he sank deeper still. Lost in pleasure, he just pawed off wildly, not even trying to swim. Though as his body's movements got slower and weaker... he couldn't surface now.
He couldn't cum as hard or as long as the adults, but he certainly came hard, writhing and bucking about in the sand. From shore, you could watch the sloshing quicksand stir less and less, slowly settling down. Deep under, his little form was shaking with the last bursts of orgasm, as his mind slipped into a pleasurable darkness. Slower... slower... it was so hard to keep awake... he slipped into a happy death, smiling as he fell still...