sectional intercourse

When the first chair clarinetist slides the bell of his clarinet over the mouthpiece of the first chair floutest and whispers slyly in her ear, “we are having sectional intercourse.”

We had sectional intercourse during band rehearsal today.
My mom doesn’t know but I’ve been having sectional intercourse since 6th grade.

This one time at band camp I had sectional intercourse.