Sleep orgasms are an interesting thing, pretty rare in my experience. Thank you for sharing!
Firstly I think you don’t need to worry too much about them. You actively don’t want to cum so your unconscious mind may well respect that and just keep you horny and denied. Worst case scenario though a sleep orgasm, unless you’re sleep masturbating (not unknown) is just a ruined orgasm. So you can chalk it up as a ruin and not worry about it.
If you do think you’re sleep masturbating however then you might be looking at investing in a chastity belt to keep things on track, but I doubt it’ll come to that.