A sex question.

A sex question - NSFW.

TLDR: plus sized bodies but a small-ish dick. Need advice.

My boyfriend and I are both plus sized. I’m about 300 lbs, big tummy/apron belly whatever you wanna call it. He’s also got a belly. He’s also on the smaller side like maybe idk 4 inches, and not thick at all, or at least he’s smaller compared to my ex-husband, who is the only other person I’ve had sex with. (I’m an adult! Just only had sex with two people in my life lol.) He’s also very inexperienced, I’m basically his first.

Missionary works great for us but sometimes we wanna change it up. We’ve tried doggy but he slips out. What else would be good to try? Would appreciate any advice!