One of the best kept secrets is how pleasurable it is for a man to be blown in his underpants. Once a guy can relax enough to let it happen, foreplay will never quite be the same. For couples wishing to explore having sex in public, it is vital that men's underwear flies become inviting and sexy, not merely a clothing barrier. There are many situations in which it is too risky to get totally naked, but dropping a guys' pants to his knees is possible and the ensuing underwear blow job is a real pleasure.
Basically, once the pants come down, you will be staring at white or colored jockey briefs (pants, slips, jocks) or trim/full cut boxer shorts. Occasionally a man will sport a thong or a bikini, but generally such individuals will wear briefs as well. Since the techniques herein only work with underwear that have an open fly, you will have to encourage the bikini or thong wearer to switch to briefs, at least for public trysts! In general, men 18 to 30 wear mostly trim or full cut boxers, or boxer briefs, 31 to 45 year olds sport a mixture of briefs and patterned boxers, and 45 year olds and up are more apt to choose tighty whities.
The fly on white or colored jockey shorts and boxer briefs is very similar, so the technique for blowing a guy through these is the same formula. Basically, the piss flap resembles an oval with a little kink in it. Put the index fingers of both hands on either side of the oval, and pull them away from another. Gradually, a very small opening will be revealed as the flaps of the brief begin to part. Move the opening to where the cockhead is pressing against the fabric and make it as wide as you can. Then, stretch the fabric over the swollen glans until just the head peeps out. You can now swallow the cockhead and press down with your mouth so that the prickshaft spreads the briefs fly one delicious inch at a time. Your guy will be moaning and grunting as he revels in the exquisite sensation of his penis spreading his briefs and entering your mouth. If the briefs are very tight, they will function as a cock ring and keep a man's prick rock hard.
When the dork is completely out of the briefs fly, put your hands up the jockeys' legs and gently cup your partner's balls. At the same time, swirl your lips over the cockhead, making sure to dip your tongue rapidly over the frenulum several times. Gradually alternate deep throating the cock with side and top tongue action, taking care not to go too deeply at first. At this point, your man will be grunting like a sweaty pig and will be working on holding back. Move your fingers up the back of his briefs and put a few fingers in his butt. The intensity of the sensations could very well bring him over the edge. At this point, you could either swallow his cum, let it fly all over the place, or have his shirt catch the cream. If the jockeys are tight it is liable to be a very powerful orgasm, so expect a lot of screaming, swearing, and bellowing. Guys that wear briefs are often skeptical about being blown in them, thinking it will be awkward, painful, etc. However, once they have experienced an expert blow job with them on, the second and subsequent times are a piece of cake and eagerly anticipated!