Even if it is a sacrifice - I feel confident he will let you practice all you want on his private parts 🙃

That sucks. (just sayin’)

You should improve your manual skill. That could...

...wait on it...

...cum in handy.

I mean...why would you say that when putting your hands down his trousers? It's not exactly a flirty thing to say. I can kinda see why if that's the kind of banter relationship you have with your boyfriend but his response doesn't make me believe that's the case.
I would recommend talking about that outside of a sexual scenario if you haven't already. I know it probably would've hurt your feelings but he could also be feeling some resentment and that's never good. Besides, communication is always a good thing in any relationship, for most situations. Talking about it you could figure out what each other want or expect from the other and maybe he could show you how he likes to have handjobs.
Also don't feel too bad, he's had his whole sexual life to practice how he likes to play with himself, so its what he is used to. May take some time for him to get used to you doing it as well as showing you how.
Good luck to the both of you :)

so you're upset that he was truthful? if you suck at it shouldn't you know so that you can improve? ydi

Whenever a sexual partner says that something you're doing doesn't feel good, you should believe them. Whenever a sexual partner tells you how to do it so that it DOES feel good to them, you should listen to them.

You know how to make a hand job better? Use your mouth ;)

I was the 420th YDI. Woohoo!
Every man will always be better than you at HJ's because they know how to please themselves. YDI for not upgrading to BJ's.

So tell him to guide you. Let you know what he likes and what he doesn’t. Unless you’ve had a dick, it’s pretty hard to know what’s pleasurable stimulation to one. And what might feel good to one might be rubbish to another.

You should have grabbed his balls firmly and said "What did you say MotherFucker?"