Keep the door open?
But seriously, you just have to decide to enjoy the frustration. Orgasm denial is not usually supposed to be some battle to endure a horrible experience. Okay it can feel like that if it’s imposed on you or if you just can’t stand not cumming, but on the whole it’s about the trade off between the short sharp pleasure of an orgasm, for the longer term ‘high’ of ongoing arousal and pleasure.
If you learn to appreciate the latter the only time you need to be strong is when you’re right on the edge and everything in you screams to take yourself over. And learning not to do that is mostly about developing willpower and self-control – orgasm denial will help you learn that.
However, in the meantime, simply don’t take yourself very close! Just gently play to keep yourself nicely ticking over but don’t try to do any ‘hard’ edges and as such, avoid the temptation as much as you can.
Good luck! It’s worth it.