Fingered myself for the first time..

It felt good when I slid my finger in but while I was in, I didn't feel much..and feeling the inside of me is very weird feeling..I was scared I was going to poke something or push in the wrong direction..I did start leakin pre cum but not really a different feeling..when I cum my ass hole clenches on my finger which feels good..just don't really understand where the feeling good part is..and feel like I'm doing damage going up my ass hole..was maybe a full finger deep