"Friends for benefits" is pooning. They are your friend so long as you are providing benefits. You're in the right place here if that's what you are looking for.
Now, if you are looking for a fuck buddy, that would be "friends with benefits", as in the two of you are first of all friends who also throw each other a little action from time to time. The key point is that you are friends with the lady. Close enough friends that you can share intimacy from time to time and still keep the friendship when either of you are seeing other people. If you can't handle that, you are really looking for either a girlfriend, mistress or a one night stand. Why anyone would think that they could find that type of friendship on Craigslist baffles me no end.
Maybe he is looking for "benefits without friends" or "benefits without yak yak yak ad nauseum,
do you have a bufferin, anacin or asprin". Personally i'd need at least a T3 or morphine.
Casual encounters seems to have a lot of offers for that kind of thing. "I'm a horny girl so horny
tonight, want to get laid by mr big, can you lick me till i scream so loud it shocks the neighbours?"
I'm sure each ad gets at least 100 responses from guys eager to service her, which tells you
what your odds are of even getting a response.
CL also has several other sections where many ladies are looking for friends, boyfriends, husbands,
long term exclusive commited relationships and, of course, what they all dream of 24/7, romance.