This is from August 2011 but I still think relevant.

Crumb now has some regret about his earlier acid-era works about rape, bestiality and incest, which began when, as a virgin teenager, he began drawing masturbation fantasies.

“I will spare you the details. Suffice it to say that these fantasies had very little to do with real women or ‘normal’ sexual activities,” he wrote in a 1994 autobiographical comic.