What you described is actually one of the methods I know of for learning to achieve MMO (multiple male orgasms),
Getting head, but when she keeps her tongue moving around the head and leaves the frenulum alone. Keep this up for 15-30min or more and it gets very intense, keep breathing with deep stomach breaths. The more you do this and manage to achieve those intense non-ejaculatory orgasms, the better you get at it and the easier it will be to achieve during regular sex. It’s really amazing stuff!