Maybe, but that doesn't mean that this hypothetical guy would be operating under same rules, social assumptions and perceived motives, while asking for that kind of permission.
Besides, i was talking about readers leniency to let such things slide, not some misty in-story universe's set of etiquette standards for sexualized behavior (regardless of other party's approval) - nobody is shrieking about "consent" in this comment section. As opposed to that occasionally happening in harem and more often, smut josei threads - presumably, because it's about two girls going at it. I can't make direct comparison in people reactions, cause i haven't seen any other series sporting that kind of vibe, based on similar wonky gimmick* ("touching your body part gives me shounen powers"), that would also feature bold male lead. Hence the word "probably".
But. But. I propose that if that kind of manga did exist, then
1) with shy x pursuing roles reversed ("dude-kun, rubbing your ochinchin helps me do whatever"), there would be zero outrage happening.
2) alternatively, if they stayed as is, there would at least be some bitching going on.
And that's great.
*there's Seikon no Qwaser, but that's not exactly it.