People are willing to take sex seriously even as they are vaguely titillated by doing so.
Disgust, however, still demands justification as a serious topic and a permissible one. Disgust invites discussions of unmentionables that tend to undercut certain pretensions and pieties we like to maintain about sex, presentability, and human dignity in general. Prissiness runs the risk of introducing the vulgar comedy one is seeking to avoid. But the very mention of some subjects, necessary subjects if we are to face up to the substance and structures of the disgusting, prompts either disgust itself or low comedy. The comic and the disgusting, we know, share significant points of contact.