Explain the "thats what she said" joke

its a sex joke basically anytime its said they mean that whatever was said is “what she said” as in thats what she said in bed last night, or while having sex ect

like if you and a friend are together hanging out and your friend stubs his toe on the wall or something and he yells “OUUUCHHH” then your friend should say “Thats What She Said”…like thats what she said in bed last night.

watch anchorman. that might help.

omg!!!

its like a sex joke. watch the office :)

Thats what she said…

omg!!!

The best description I have found so far (copied from JustWhatSheSaid.com):

that’s what she said [thuhts hwuht shee sed]:

1. The most versatile joke on earth
2. A phrase used to turn an innocent comment into a sexual joke

Ryan: I brought that box of staples from the warehouse Jim: Just stick’em in the back if there’s room Michael: That’s what she said!

• The Office

[Brian and Peter are putting a crib together.] Brian: Okay, insert rod support A into slot B. Peter: That’s what… Brian: If you say “that’s what she said” one more time, I am gonna pop you. -Family Guy

Anytime something is said that is a double entendre, Michael says “that’s what she said” referring to the other possible meaning of the phrase. I.e.

“Wow that’s a really big one!” -referring to a truck or something normal. “That’s what she said!” -referring to what a woman said about him.