Rough blow jobs?!

Chloe
Okay... Me and my SO have been together roughly a year. His sex drive is very high and in turn mine as well. 
So... The other night I went to give him a blow job because he got me off first. He jammed his "Manhood" into my mouth and I wasn't expecting it and it hit my teeth because I didn't know it was gonna happen. Any tips or advice for avoiding teeth? 
Kinda embarrassed and I don't want it to happen again. Please help. 😳