Side Dong 

When a man wearing ill fitting undergarments inadvertently or on purpose exposes a portion of his penis, testicles, or combination of both

Did you see that old man in the speedo he was flashing some serious side dong.

Side Dong by Gary Gnard November 21, 2022

Dong Side of the Moon

While mooning one party, accidentally flash your dong to an unsuspecting third party.

When Logan mooned Weil, he accidentally put his dong in Mitchell's webcam. I hope Mitchell likes Pink Floyd because he just saw the Dong Side of the Moon.

Dong Side of the Moon by Dr. Goonsworth September 4, 2012