Girlfriend wants me to cum involuntarily/handsfree

We recently discovered that my girlfriend has a kink for me cumming super fast and we're super interested in me cummimg involuntarily, in my sleep, while cuddling, or even in my pants out in public.

We're working on not giving me any full orgasms (ruined only at most) and I've ordered some l-histidine to hopefully speed up the process.

My questions is: If I get to the point that I can cum just from arousal or a super light touch will it be more like a ruined orgasm? Where im unfulfilled and still horny? Or will it get to the point that I have full orgasms and lose all interest?

If anyone here has experience with this or if you have general tips for ruining my endurance I'd love to hear it.

TL:DR: want to cum extremely fast but maintain arousal