A tutorial, as requested. Requires Photoshop CS2 or higher for easy following, but if you're clever you can work it out in other programs. Blurred boobage so that I didn't have to keep my secrets from the under 18 crowd, though I don't think one nipple would really freak people out that bad. Still, don't want to disobey the rules. :D I'm no rebel.

Steps 4-5 of 7.

[Steps 1-3] [Steps 4-5] [Steps 6-7]