Aw, that’s so sweet! It’s common not to orgasm the first time someone goes down on you (especially if the person giving it is inexperienced). I’m sure he was disappointed because no guy wants to let you down! He wanted to please you! Just reassure him that you did enjoy yourself and tell him that you really want to try it again (and again…and again…and again…).
The key to oral is rhythm and never BREAKING that rhythm. So my advice is that when he hits a good spot or does something that you really like, make sure he KEEPS doing that and don’t fucking let him stop! It’s about working you up, finding that pace, and then keeping a steady/increasing rhythm until you break!
Try to help him more next time, give him guidance, lead him where you want him, and if he does something really good, physically hold him there and tell him to keep going just like that!
He’s not a failure – I know you know that – but guys shoulder a lot of the burden and the ones who care about your pleasure really take it hard when it seems like they’re unable to give you what you need. Again, reassure him that you enjoyed yourself and you really want him to do it again. (Don’t overcompensate by drawing attention to your lack of orgasm, that makes it worse, just continue to show sexual interest in him and an eagerness for more.)
Sex is all about experimenting. The more you experiment, the more you learn, the better you get. So…tell him to get back down there and try again! The sooner the better! And make sure you relax! You guys will find a way to make it happen.