Agreed! Waste not. And even if you hate the taste of cum or don't particularly like giving blow jobs - which I don't really understand, because I love it - he's going to be a lot happier if you enjoy it. Make it seem like taking him into your mouth is the best thing you've ever experienced. Show him you're into it by looking at him while you suck his shaft.

And your mouth doesn't have to be around his penis the entire time. In fact, it can get tiring and tedious to just keep moving him in and out of your mouth. Use your hand if your mouth gets tired, but make sure it's lubed or use your saliva to wet it. When I'm giving a blow job, I tend to salivate a lot more.

My guy goes wild if I take his balls completely into my mouth one at a time, sucking hard and then releasing them in a constant rhythm. But don't go too quickly or pull too hard, and you can stroke his shaft while you do it.

Overall, though, you have to ask him what he likes. You can experiment with things that are suggested by others, but if he doesn't like it, he will tell you, and you can try something else. I learned from trial and error, trying everything I could think of.