I don’t know how sexy it would be per say but the imagery of someone outgrowing one of those really old diving suits like what you’d see in Scooby doo might have some appeal to it if not just be fascinating to watch.
I’d have to say pants of any kind. My wife was already a beautifully large sweetie when we met 10 years ago, but has gained probably 60 or 70 more pounds since then. Watching her belly and waistline get soooo huge and soft is beyond words ;-) It’s of course summer now, so she’s really become proud of her body this season with the most lovely plus-size dresses that show off her softness. She is my beauty queen forever ❤️
I feel like workout clothes would be. They are basically optimized to help and make you comfortable while you lose weight, so to outgrow those would be kinda hot