Giving head

Okay so I know this may be a kinda silly question but I need to know what others think. I hate giving bj’s like I find the whole thing so unenjoyable and it always seem to last forever until he cums. Now my question is, what do you do when he cums? Like they say spit or swallow. I’m certainly not swallowing, so where am I spitting? It always ends up so messy and I can’t deal with it anymore. When he cums in my mouth I literally start gagging and I don’t know what to do. Please help someone