Doonesbury by Garry Trudeau for December 27, 1990
Soldier: Hey, man, you really did time in 'Nam? B.D.: That's right, kid...and let me tell you what the number one lesson was: no matter how frustrating, it's better to be sitting on your butt than having it shot at! Soldier: Wow...what was the number two lesson? B.D.: Always check your underpants for scorpions.