User blog comment:B214/Question and Answers 2/@comment-96.255.45.78-20140522022705/@comment-16281343-20140523231516

That's because that is an essential part in that story. The Qwasers to suck breasts. The same with the MC of the series "Kensen Robo Daimidaler" where he needs to grope breasts.

DxD isn't like that where it's explicitly stated that the only way to power up is to do something with breasts.