"Oooooh fuuuuck, my glob, yes, yes!" Sandy screamed as her orgasm radiated out through her body and left her limp and quivering. Nearly simultaneously Bob let out a primal, animalistic series of grunts and groans as he also climaxed with great intensity. He then pulled out, rolled over and tried to catch his breath as he lay on his back next to the spent squirrel. "That was fucking amazing!" gasped Sandy. "Yeah, it never gets old does it?" agreed Bob. "You know Bob, when they sent me down here to study the affects of the nuclear bomb testing that they did at Bikini Atoll I never imagined that I'd find a town called Bikini Bottom that was populated by sentient invertebrates. So imagine my surprise when one of them was a mobile sponge who was not only charismatic and charming, but can also fuck like that!" "Hey, I was just as surprised to learn that there were land dwelling mammals out there. And that I'd find one of them physically attractive," replied Bob. "Even more surprising is I had no idea what copulation was like! Hell I didn't even know that inter-phylum sex was a thing!" "Really?" asked Sandy, "You never encountered any other sponges like yourself down here?" "Oh there's a few around. But even though they're mutated from the radiation leftover from the bombs, they're more conservative, more traditional." "How do you mean?" Sandy queried. "You're a scientist, you should know about Poriferan reproductive biology," snorted Bob. "Oh, I see," said Sandy. "Yeah, just ejaculating your sperm out into the water and hoping that the currents carry it to another waiting sponge isn't nearly as fun as pounding away on a tight Sciuridaen pussy." "Mmmmm, Bob," purred Sandy, "I love when you refer to the Latin name of my familial classification, you naughty Demospongiae you." And with that she crawled on top of him, kissed him deeply and reached down to massage his cock and balls to help get him ready for round two.