In all honesty, I'm a tad Switch, so I'll post both fantasies here. (Promise not to tell...these are like....deep dark secrets I only just admitted to My sub!!)
Domme: Listening to the delicious cries for mercy and hearing My Pet call herself a slut and a whore repeatedly as she is strapped to the bed, My fingers in her slick pussy, letting each surprise I inflict on her draw better and better responses until she can't even speak. Frankly, this makes Me wet thinking about it now.
sub: Being drugged with something like ecstasy....anything that would increase sexual sensation.....then seduced by a total stranger (probably a man; funny that I'm only a Domme for women and only a sub for men) who ties me tightly but with silky fabric (this fantasy is all about touch) and then basically gropes me as he has his way with me in a number of different positions, possibly involving a swing....yeah. Yummy.
By the way, this makes me want to start a thread on Switches and their gender preferences....