1. To be able to take part in sexual activity following a period of time where one could not due to medical or personal issues.
2. To serve a purpose related to sex.
Following the birth of their son, Bill hoped his wife would be fucktional again sooner than she was for the birth of their daughter when he went four months without sex.
Used to say that your sexual equipment package is still in working condition after receiving physical trama
Guy 1: Dude you just took a direct hit to your junk! Are you alright?
Guy 2: I think so, everything down there still seems fucktional, i better go see my girlfriend and make sure.