Definitely talk to him! If you’re feeling nervous about it, you need to explain exactly that to him – let him know what it is your feeling/thinking. Guys need us to spell it out for them, they respond well to a direct “this is what’s going on” approach. They do not understand mixed messages and get confused very easily so the best form of communication is the one that is as straightforward and honest as possible.
What is it exactly that you’re worried about? Some white stuff is gonna come out and you just wipe it off with whatever you have handy. That’s it really. Just make sure you’re not in the way so it doesn’t get on your clothes and make a mess. Also don’t let it get in your eyes! Burns like a mofo. 😉
If you’re really worried about taking it all the way to the finish line, try this: do what you usually do and then when he gets close, instead of stopping altogether, have him take over. Tell him to finish himself off. So he’ll jack off in front of you and you can watch and see for yourself without worrying about the responsibility. He’ll think it’s hot if you ask – anything so that he gets to come! Once you see it the first time, it’ll never be a big deal again, haha.
Do you want me to post some “cum shot” gifs for you so you have an idea of what it’s going to look like?