My friend Sean, a natural, actually seems to get "word of mouth" sex. He is notoriously easy and forward so in any social circle he is instantly showing that...

He finds that as long as he makes no promises with the first girl, if he lays off for a couple months while staying friends, he becomes just one of the people in the group, and some girl that might have heard how good you were could put the moves on you. This has yet to work for me but I have seen it work first hand with a natural.