You might talk with him about slowing things down. Play with him some and let him play with you. Try some mutual masturbation. You can also work yourself up for a short time. That will make it easier for you to orgasm and get him excited. If he's never seen you masturbate, you're going to be surprised at how excited it makes him. If that doesn't work, you can always look into delay creams or sprays, but only if he's interested in it and only after you two have talked and you've tried other things. If you're not careful, it can turn into a difficult conversation.