wait. if I'm reading Cummean right, you get less penance for masturbating with a friend than on your own. if "boys of twenty years" masturbate together, it's 20/40 days penance. but if a man masturbates alone, it's 100 days. Huh. I wouldn't guess that hanging out together was the way to make your masturbation less sinful.
Those are first offenses, of course. there's like, a scale you go up if you repeat it.
Also, everyone's favorite "used to be huge, now fallen out of the zeitgeist" type of sex makes an appearance: Intercrural sex! (aka thighjobs). Here called "femoral masturbation", a wild term I've not seen before today.
They're mentioned so they can be not as bad as sodomy. a thighjob with your bro is 100 days, then a year each time you do it again.
While sodomy starts at a year, goes up to two, then three, and then "if it becomes a habit" (and sodomy so easily can become a habit), seven years! and "a method of penance shall be added according to the judgment of this priest". Zero idea what that'd be.