Any advice for taking big dicks?

I finally pulled the trigger and started experimenting with another guy recently... it's been going a lot better than I expected, and now I'm at the point where I'm ready to try bottoming.

Only problem is my fuckbuddy is hung like a damn horse. Not just long, but thick as fuck too. I've tried sitting on it a few times, but I always wimp out before I can get even halfway down that monster.

He's not any help either... he's also new to trying gay shit, and says that girls always wimp out at the halfway point too. He's actually pretty frustrated about it, says his dick is so big it's useless. I thought it'd be hot if I could be the first person ever to take him balls deep, but idk how the fuck to manage it without killing myself lol. Any advice on good positions, maybe?