Topic says it all. How would you diaper the Megaman girls? Not dress, how would you imagine them being diapered. Bedwetting, injury, secret like, forced, punishment, what? Try and be unique as well. I'll give a few examples.

Maylu: Bedwetting
Ashe: Injury
Cinnamon: Remodeled to be more human like, and needs potty training.

Anyone else?

Maylu: Punishment. For such a sweet girl with an innocent character I imagine her mother wouldn't employ too harsh of punishments with her thus a gentle but lasting diaper punishment would be in order and would serve to keep them close as mother an daughter.

Aile: Teen Baby. Aile lost her mother at a young age and while on the outside she is a strong determined young lady deep down she is lonely and misses her dearly. Getting back to those memories of younger simpler times in a diaper would be her secret relaxation of choice.

Classic series Roll: Cuteness. I think classic Roll enjoys cute clothing and being the little girl of her family unit and secretly under that red dress wears a cute diaper with prints.

Those are just a few I can think of on the fly. Anyone else?

I'd diaper mayl/maylu through setting up am elaborate trap that diapers her as soon as she sits on her chair in her room that's disguised by a cloaking device