The act of masturbating.
Originally coined in a EuroPop song in the 1980's by Men Without Hats. The song includes such phrases as:
"We can dance if we want to, we can leave your friends behind"
"We can go where we want to, a place they will never find"
"Everybody look at your hands"
"As long as we abuse it, never gonna lose it
Everything'll work out right"
In a overly-hyped, but dawning era of AIDS in the 1980's, masterbation and abstinence were considered essential safety behaviors - masterbation being the Safety Dance.
A similar song was Billy Idol's "Dancing With Myself".
"Where's Steve?", Dana asked.
"Oh, he's probably in the bathroom doing the Safety Dance", replied Dan.
SSS-AAA-FFF-EEE-TTT-YYY SAFETY DANCE!