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!
It's the future of sex. Sex with hot robots. They feel surprisingly soft, but can turn tough and durable during battle mode. It's based on smart metal. It's a metal that's already under development, but will be fully developed in the future. It's a metal that can change material properties at will(they could get soft, smooth and squishy like normal or wet human body tissue, but get tough like steel during dangerous situations and battling). Girl sex bots. Sex-bots.
Dude 1: I like Jenny XJ9.
Dude 2: Well. Once you go metal you won't want to settle!
Basically, It's the future of sex. Once a sexy female robot comes around and you have sex with her, you won't want to settle for less. With robotic women: no STD, no pregnancy, no condom, no problem. The term "Once you go metal, you won't want to settle can be seen in a poster featuring Jenny Wakeman(XJ9). Jenny XJ9 is an attractive robot from the show "My Life as a Teenage Robot". It is after XJ9 got the 18 year old upgrade in rule 34 that the term, "once you go metal, you won't want to settle" began to be used. It get's hotter. Jenny wakeman is hot! Jenny XJ9 is sexy! Jenny Wakeman is from the show MLaaTR. I would pick Jenny XJ9 over a human any day.
Random Dude:*Jumps on Jenny the gynoid robot and has sex with her.*
Jenny Wakeman:*Does guy for 5 hours*
Random Dude:*Continues to have sex with Jenny XJ9.*
Random Dude:Oh yeah!
Jenny Wakeman: Wow!
Random Dude:I want more!
Jenny Wakeman:You can't be serious!
Random Dude: Yes! Uh! Oh! Energizer bunny:Once you go metal you won't want to settle.