User blog comment:B214/Question and Answers 4/@comment-24866657-20141019162746/@comment-1359322-20141020090010

Actually i think the amount of demonic power has little to do with the effectiveness of Dress Break and Billingual. Demonic Power requires imagination, Issei's imagination over a naked female body and breast are probably the only requirement for Issei to activate Dress Break and Billingual.