When someone is saying "Slap-A-Doodle-Doo" it means that one said a funny joke, but the joke wasn't funny enough to laugh out loud at.

Adam: Did you see Sarah? She lookes like a squashed pickle.
You: Haha nice one! Slap-A-Doodle-Do
"A non example would be"
Adam: Did you see Sarah? She looked like my deformed dick.
You: No way dude LMFAOOOO, Shit you hadda go there dawg OMFG LMFAOOOO

"I had a lot of cartoon characters that used to get me sexually aroused as a kid... The female reindeer from the Rudolph claymation series, when I was in preschool, I used to be bricked up watching that shit." -Jack Harlow