You want to learn control. As she is providing the HJ start thinking about a fat ugly chick. See how long Mr Happy stays awake.
This is not a theorey, as I do this whenever the session is getting really bad I just use my mind, and whoala I can go limp. Sometimes when I want to redirect the session (like let her know we need to do some more foreplay events before she starts to jack-hammer Mr Happy). Guess what the mind fuck works in reverse during a HJ, so if I want to c*m then I start thinking about the MPA's legs, breasts or any nasty shit I would want to be doing with her, and whoala Mr Happy starts to sputter. Also giving her a few verbal tips on how the HJ is going or not helps (like redirecting her to use some more breast massage on Mr Happy to jump start things, this can salvage a too quick body slide).
Do I need to pay muchos denarios to find this out. Perhaps I need candles and wafting incense in a dimly lit room to figure this shit out.
Controlliong Mr Happy with your mind is like sp101. If you want to control the flow of a session start with letting your Big Head control your LittleTantricOrgasmicHead.
JM2C
Lou