Ok, so I have a lump inside the crack of my bottom. It feels like skin, but theres also something hard inside of it, like puss maybe. If I squeeze it, it shrinks for a bit then goes back to normal, I would say its about a it bigger than a pencil eraser. I do not know how long it has been there. This is pretty embarrassing to tell to my parents, so I would like to get opinions on this first.

get it checked out immediately. my boyfriend found out he has stage 4 melanoma when he found the same thing you are describing. don't wait to get it checked out! melanoma is a very aggressive and fast moving cancer.

Well, my first reaction is that it sounds like a pimple and not to worry too much. You didn't say how long you have had it - so you could always give it a little time and see if it goes away. If it doesn't then you should have it checked.

If it doesn't seem like it is a pimple to you at all, then you might want to have it checked right away.