Chase, go find the book "She Comes First" and maybe "The Guide to Getting it On". Both have great sections on how to do it.... and what you're facing.
Here's the PDF file of the first book that you found:
So, you're only 15. If you're going to engage in this type of behavior, you might as well study up, so that you don't hurt yourself or anyone else in the atempt, right?
You know how to read at age 15. Go find these books either at your large bookseller, or on line, at someplace like Amazon.com or ebay, or similar. If you want to know bad enough, you'll get a book and read up.
PS: Another book, mainly text, is "Everything You Always Wanted to Know About Sex" by Dr. David Rubin. There are LOTS of used copies floating around used paperback book shops and second hand stores. I'm not certain that it addresses what you asked, but it sure wouldn't hurt to read up from cover to cover if you're going to engage in adult behaviors.