Most bottoms are too shy to ask, but I've had several ask me to stay inside them after I cum, something that is incredibly erotic and actually romantic. Just being inside the person after you've finished ejaculating into them, feeling the warm, wetness of their rectum against your penis, feeling them squeeze your penis with their sphincter, the smell of ass in the air, just heady stuff!
to mdo1985 :that's why a threesome is great ... you wait while the 1st guy shoots his nutt and you feel his cum when you slide your cock in ... all the feelings you describe :-)