I've done it with a razor before. Of course, I didn't just do the chest, I also did my stomach, shoulders still do that one) and my man area (ditto). I find that some women like it at first, when you're first going out but then want you to grow it out so you're more "safe". Now, I just keep it trim unless I'm going to a lingerie party or something like that, then I might shave it. I never got red or itchy, even when it was growing back out. However, you do get prickly in a few days so you either have to keep shaving it often or risk exfoliating any woman that tries to lay on you for the next 2 weeks. Also, as it grows back, it'll look patchy for a little while... not the most attractive look my friend. Muscle definition-wise, you can't beat a clean shave. If you actually have them, you won't ever look like you're 12.