Bumping into her cervix?

It is her cervix. If it doesn't hurt her then ok, but it is very painful for most women. There are a lot of techniques you can use to prevent bottoming out. the easiest for me is to create a backstop using the palms of my hands against her thighs. That way you can go for it with 'gusto' but your hands are there to provider just enough space to prevent bottoming out. You have to remember that the average vaginal cavity is the same depth as the average male penis. Funny how nature made that work, right? So 99% of females you encounter will bottom out somewhere in the 5-6 inch range. Some are more shallow, and some are deeper.