Biking. Almost everything you can say while huffing & puffing along is a perfect set-up for a "That's what she said!" punchline.
"Hey, your water bottle fell."
"I know, I felt it hit my leg."
"That's what she said!"
Getting off my bike seat after a ride, "Damn, my ass hurts."
"That's what she said!"
"Blech! A bug flew in my mouth. Oh well, just extra protein."
"That's what she said!"
And so forth. "Hey, slow down a bit," or "Can't you go any faster?" "My ride's getting a little rough, did you bring any lube?" After a steep hill, "Damn, that was a big one." "I'm tired/sore, can we rest a bit?" "That was a good ride, but we should go a bit longer next time."
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"Returning hate for hate multiplies hate, adding deeper darkness to a night already devoid of stars." - Martin Luther King, Jr.