Apparently Mark Judge was calling someone Bart back in the day, not just in later penned tales of debauchery. "Bart have you boofed yet" is probably a bit of a head scratcher for most folks reading Mark Judge's yearbook attributions.
I was a teenager in the 80's, and "boof" was a little bit of slang we tossed around, thinking ourselves funny. I think "bufu" was also in somewhat common use. I don't know what "boof" meant in Brett Kavanaugh and Mark Judge's world, but I recall it to mean the act of having sex with someone in the "back door", as we would have said.
What an odd thing for this guy to include on his yearbook page. Kind of the thing you'd expect a couple teenage partying, self styled lotharios to toss out at each other. And in line with some of his other remarks. I'm sure "Phil's homecoming date service (YEAH BOY)" is just reference to some good clean fun too.
These two are straight out of central casting (hat tip to our National Disgrace) for the role of "privileged kid who thinks he's God's gift to women and has chalked up several date rapes by age 20" that I swear I've seen half a dozen movies about.
Don't worry, Brett. I'm sure this quality only endears you to our National Disgrace more.