Nut cream is a
complicated sexual act which probably will become popular in porn movies very soon.
1. You (the man) fucks a girl in the ass and cum on her asshole (note: not in her asshole).
2. When the sperm lies there on her ass you take a hold off your balls (hence the term "nut") and puts 'em down her asshole, then begin to "ballfuck" her.
3. Take out your balls, now dripping of sperm and "
brown sauce" and let the girl
take a lick (or suck).
This is what you call "nut cream".