Once you go metal you won't want to settle
Once you go metal you won't want to settle means that, once you have sex with a robot, you won't want to settle for less. I'll take a gynoid robot over a human anytime! It seems that definitions like this don't get published because the Urban Dictionary is being run by rebublicans. REBUBLICANS! Examples of this are futurama and also fans of MLaaTR.
Fry:*doing lucy liu robot.*
Bender: What are you doing to that robot?
Fry: Hey! Once you go metal you won't want to settle.
Dude1:*Doing hot Jenny Wakeman robot*
Jenny Wakeman: Oh! You're soo good!
Dude1:I can't stop. This is way too good!

*5 hours later.*
Dude1 (still grinding the gynoid robot): Once you go metal you won't want to settle. Oh yes! Uh! Oh!