It is a fine thing to touch one's own cock for a variety of purposes.
It is a TERRIBLE IDEA to do the second directly after the first without washing one's hands THOROUGHLY in between.
"Gee. My penis appears to be on fire. That is not a pleasant sensation."
It doesn't SEEM like something that you can't feel at all on your fingers should cause your wiener to feel like it's covered in flames, but it does. It really does.