A sexual act in which a male attempts to place his testicles into the asshole of his partner (preferably female but male-male action is possible also). Ideally, the asshole being to tight the testicles will
repeatedly pop back out like a when you try to put a
dog in a bath tub. The asshole should be well lubed and loose enough to allow partial testicle
penetration. Not an ideal position for virgin or gaping assholes.