He probably has a Hella ton of experience with the side effect of his jester job, and we have to take into account his playboy nickname (where there's smoke, there's fire) .
Also remember that spontaneous interlude scene with the goddess on his job change? I think the goddess actually really enjoyed herself with his um body I guess, I remember her praising him for something very vague (and it's probably the you know what).
And it's actually refreshing to see um an experienced MC that actually takes the reign in this situation especially in these types of fantasy stories. Of course the boobs are a little out there but really they're not too out there among common porn. (Basically the boobs are actually in their element in this chapter)