Withdrawal
This is The Lounge Lizard's preferred method, not that condoms are bad, I use those with pixies and breeders I don't know, usually the ones I meet at clubs, but when doin' the nasty with a familiar booty I prefer this method.
It works like this. As you're pumpin' the broad between her legs with your pecker, you start feelin' the urge to nut, that happens, it's what you bone for. Anyway, when you start feelin' that urge you pull your fireman out of that there hole and let him spit all over her pretty little body and face, thus preventin' any kind of insemination to happen (that means gettin' her pregnant). Unfortunately, it's a skill that needs quick reflexes.