Help! SEX!!!

So, my bf and i are just starting to become sexually active and he’s uncircumcised and his penis is pretty thick. I’m 4’9 and curvy but everytime we try to have sex it HURTS me so bad. We tried again today, and I can tell he’s starting to get frustrated at the lack of penetration cause he was actually trying to put it in. Anyway I can help myself open up a bit more??? I enjoy seeing him wanting me but it’s hurting. ;(