I did use the guide before I was forced to get here.
I tried again after few IG days (around 2 weeks) and in the meantime kept repeating Carlas "nipplefuck" and other options she had and when I went to tea party again got different dialog from Velena and Sandra on 1st try so I guess "brute forcing" by skipping days and repeating actions fixed a switch that didn't get activated the 1st time????
Also a note I did have a crash when hitting f12 so that might have done something to the save as well.
You need to nipplefuck Velena, and then talk to Sandra. Keep talking to her till you get dialogue that will trigger the quest. You don't need to go away and try another day, just talk to Sandra again. The quest doean't require to be triggered when you see witches first time (in fact. it is impossible to do it) - you just need to nipplefuck Carla at least once, go to the tea party, nipplefuck Velena and then talk to Sandra till you get right dialogue.
F12 closes the game in RPGMaker games. in a non recommended way. It conflicts with mouse script I use, which is causing the crash, but I guess if you want ot force close the game, the crash still works