If you are using Rez Hacker then simply copy and paste.
Ok, scroll down to the body parts list and change the end -1 to 2 on either cheekL or cheekR depening on which cheek you want to kiss.
45, 18, -1, -1, -2, -3, 8, 2 //8 cheekL
or
45, 18, -1, -1, 0, -3, 8, 2 //9 cheekR
Scroll up a bit to the textures list and change the \art\autobuild\cottonwhite.bmp 0 to \resource\clothes\nameofyourbmp 0
For example...
[Texture List]
\art\autobuild\hair3.bmp 1
\art\autobuild\clear.bmp 0
\resource\clothes\abs_lipred.bmp 0