How to bottomm

Sooo I was going to do it yesterday and I had prepared a lil bit with my fingers and stuff but I realized I didn't go as deep as I should've myself because he went waaayyyy deeper with his finger and it hurt so much, like I didn't feel pleasure just pain plus it felt like I was about to poop he tried putting his dick in but he couldn't fit anything cause I was too tight. I ended up just sucking him (also my first time) and made out until he came. Sooo how do I prepare better for next time