I think the penis man should install a taste sample glory hole wall on the side of the truck. I would gladly volunteer my services for providing the samples, no pay needed.
Uh, ... major conclusion on my part is that Karma-sensei, in his own inimitable fashion, has dramatically answered the age-old question: "Where's The Beef?"
And, if I read the story right, it's the first time I note said artist creating a FMC in one of his stories, who qualifies as a Sexy Onee-san (relative to young Kouta-kun).