It signals your interest; it establishes that he's interested.
It's the third physical act you engage in with a new acquaintance (after touching his chest or shoulder and kissing).
It's the first physical act you engage in to initiate sex.
Groping a friend is an important way of demonstrating chummy affection, like patting the shoulder of a straight guy).
There's nothing more embarrassing than going in for a grope and feeling nothing. So it's important to know some ground rules.
1. First, determine if he's into it. Groping without consent constitutes "sexual touching," a misdemeanor. Fortunately, it's rather easy to figure out:
Touch a few other body parts first. Work your way down from shoulder to chest to knee to thigh. If he doesn't give you any "back off" signals at any point, you're home free.
2. Ignore that bulge in his pants. A bulge in his pants isusually his wallet, or his handkerchief,
or just the way the fabric hangs.
You don't want to be grabbing at nothing.
3. Look for the wrinkles. For guys of ordinary size wearing trousers with a regular fit, the cock and balls slide to the left or right of the zipper, invisible. But the fabric stretches slightly to accommodate them. The cock and balls here are on his left, just next to the zipper line.
4. If you see nothing, grope left. 90% of guys dress left, pushing their cock and balls to the right side of the zipper, probably because if you're right handed, it's a natural place to put them.

5. Don't ignore the testicles. The purpose of the grope is not only to indicate your interest but to help him become aroused, and stimulation of both cock and balls produce the extra blood flow that results in arousal. Besides, in most guys, most of the package consists of balls, with the cock a sort of afterthought.
More after the break.



