In a student election, Jerry tells everyone that Milton doesn't shower after gym class. Milton confides to Julie that it's because the water is cold and there are boys in there.
In Kim of Kong Milton plays the part of a jilted lover when he finds out Kim's been sparring with Jack: "Please don't tell me you sparred (slept) with him! Here! On our mats (bed)!" (Milton runs out of the room and reappears a moment later, drowning his sorrows in ice cream) HOW IN THE HELL DID THAT GET OUT?!
When Rudy meets the woman dressed as a cat he tells her he knows a lot of knock knock jokes. The woman tells Rudy he should start knocking. The look on Rudy's face just sells it.
In Reality Fights, Jack gets hit by a tennis ball. The fact that he was clearly in pain and his voice became high-pitched should be a good indication of where he got hit.
In New Jack City Milton wanted to have a piggy back race with Kim and Carson, so he jumped on Jack's shoulder and smacked Jack's butt onscreen.
Jack:Did you just-
The episode Kickin' it Old School Rudy asks the teacher if he can clap her erasers.Also, the apple eating scene.
I'm pretty sure Rudy tried to jack off a bull in Witless Protection
In "Eddie Cries Uncle" Jerry tries to adjusts Eddie's balloons and Eddie tells him to knock it off or they'll pop. Keep in mind that during this moment, Eddie is disguised as an old lady so the balloons are basically fake breasts. When Big Easy hugs him, the balloons pop.
In "Witless Protection", Rudy says his finger has two purposes: the first is to point at criminals and the second he doesn't feel comfortable saying it in front of the cop.
In another episode, Jerry thinking an old lady is Rudy disguised, asks "him" if he wants to "lie on the mat and sweat a little". The lady then hits him with a tray.
Probably the most obvious and literal example so far is the duck poop storm in "Jack Stands Alone".
In the second episode, Jerry and Jack smack their school's sumo champion janitor's butt while he's wearing nothing but a sumo diaper.
Jerry and Jack: *at separate times* Whoa, skin on skin. *singsong* Awkward.
In The Wrath of Swan Jerry says he was going to the dance because Milton paid him $60 and let him see his turtles go at it