Why not both? A #Fapstronaut can be anyone exploring anything involving the #fap!

...now I'm picturing someone wearing a space suit as they get bukaked, and the visor gets all whited out with cum...

And another thing, the term #Fapstronaut should refer to someone on a journey to explore new and interesting depths of masturbation and sexual expression, not someone who's afraid to masturbate: that's not a Fapstronaut, that's a #Chasteronaut, and if you're really into that, I know plenty of #dommes who'd be glad to put you in a cage and REALLY forbid you from cumming!

(Not me though, I'd rather you cum often, and #masturbate to weird shit. #Fap on my #Fapstronauts!)