A few people have had some difficulty getting the G1 Male nipple skin patch to work correctly on the first pass, so I want to offer a simple solution and explain a few things to help people understand how the patch works.
If your skin patch doesn't work right away when you log into SL, here is how to fix it:
Solution:
Enter Appearance, bring up one of your skin sliders (Skin Tone, Ruddiness, etc.) and make a 1% adjustment on one of the sliders. "SAVE ALL", then exit Appearance. If you need exact settings, just go back into Appearance and adjust that 1% change back to what you originally had, and save out agian.
Explanation:
To see permanent in-world changes to your avatar's character files you need to make an in-world update in Appearance. The servers that Linden Labs uses to collect data on the status of your avatar read each and every *.tga file in the character folder whenever you make any change in Apperance. Those files then get updated and saved on the SL servers and distributed to all other systems logged into SL that are in range to read this data. Installing new files in the character folder and logging into SL is not enough. Some sort of Appearance change must be saved in order to trigger this update. This proceedure is detailed in the Skin Calibration and Toubleshooting section of the Second Skin Manual.
PLEASE DON"T INSTALL THE PATCH POSTED HERE UNLESS YOU WEAR A MALE G1 SECOND SKIN!