Yes, sisroom is buggy, the game is a bit messy.
I cooked up a quick fix for these two problems, this should fix the dildo scene and that repeating scene about talking with Nicole later on. It also enables the dev console.
Just download the attached 7z file and extract it into the 'game'
subfolder inside your game root folder (root is where the exe-file is).
Let it replace Sisroom.rpy and script.rpy files, it also adds unren-dev.rpy and nine image files into the 'images\1\sisroom' folder.
Those images are already there, but they have different names - I had to rename them to fix the first problem and it's easier to patch it this way, just by adding the same files with new names.
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Update:
A new and better fix is here:
You must be registered to see the links
Removing old attachment from here as obsolete.