Femdom with my girlfriend

So me 18(M) and my girlfriend (19F) have been together for almost two years. we have tried many different things in the bedroom. however my main kink has always been femdom, i don’t want to ruin our relationship by brining it up but i also want to see if she’s interested. the most “femdom” thing we have done is a tiny bit of ballbusting like just squeezing and punching. other than that she makes me call her mommy whilst we have sex. how should i go about introducing her to it and talking to her about it.