Considering the hostage situation, I'm sure Sayuri is not in the best mental state. Perhaps some wholesome words of comfort or even some words of protection would guide Sayuri towards a path of sexual healing.
I think the mothers' would be good friends and have a book club/girl's night out. Perhaps some lewder book suggestions or some lewd, drunken dances from Yasuka would put Sayuri's mind elsewhere from her worries.
Maybe some nights, Sayuri couldn't bare to be in the house where her daughter was accosted by that Ugly Bastard and would ask her best friend Yasuka, and her daughter's boyfriend/sex-friend if she could spend the night at their place. And perhaps a particular passage in that week's book or maybe a few too many drinks bring the two mature women to propose a little fun with Saito.
Consequences would arise from this night of passion. A knowing look of guilt over what she's done with her own daughter's boyfriend/sex-friend whenever she sees him near anything of her daughter's.
Some other ideas I had were some sweaty yoga with a whole slew of potential grinding options. Thighs of course, but also maybe some shaved armpits, titjob, and other fun yoga positions.
If yoga feels too cliché, maybe the house becomes a mess due to a depressive state that Asami's disappearance has brought on. She needs some housework to be handled, and we gladly accept the extra challenge. I could see something leading to a gloved handjob scene, just an apron on for a thighjob while doing the dishes, feather duster/tickle play, and a shower scene. Maybe we even start cleaning out the old crawlspaces, and discover something that brings her to tears and we comfort her. Oh and she might get stuck on purpose ;)
I do think that her mental state should definitely be explored, almost as much as her body! Excited for May!!!