I've never seen a scene with a sex toy in this game. Are you talking about the new version (v0.19.0)?
It's actually Sex-doll, sorry I wrote it wrong, it's something with that old lady
Whem you finish the main story content, you unlock the sex-doll character type (the old lady is not available yet), the senpai girl should appear when you spend time on the swimming area at the end of the afternoon.
