How to open up to my gf about my Abdl kink?

I really want to ask my gf to try diapers for me and/or try being in littlespace. I just dont know how to go about broaching the subject. She already has an idea about my interest in ageplay, she dresses up rather 'cutesy girl' for me often, but i worry this may be pushing it. She isnt disgusted by them, and has had "adult relations" with me while i have one on (when my ic is flaring up) and we roleplay all sorts of other kinks, mostly in a bdsm theme so she is certainly no prude. She has mentioned previously that her only hard limits are bodily fluids (i dont expect her to use them) but although she hasnt specifically ruled out diapers, i feel when listing things that are no's, the whole diaper/Lg thing may never have crossed her mind.