Make a variable that it a boolean and also put a timer. So when you are in "slowmo"and you push the key. You check two things. if "slowmo" its activated and if the variable "slowmoKey" is false. also check if the timer its paused. if it's false, put the game on slow mo and start the timer this would prevent to switch automatic to the true state (also sometimes work the "do it one time " But I like to have a double check. When you want to deactivated would be the same but check if "slowmo" is True and "slowmoKey" is false. Because with the timer your are going to put the "slowmoKey" is true, that's your safe secure. When the timer reach, like 1.2 sec. you "slowmoKey" into false. reset the timer and pause it. This is the way I do it, I hope isn't a mess. AI explain really well this.