Can I get a venereal disease if I put on a vaginal disc that fell on my toilet seat?

If you rinsed the disc under running water, the risk of infection with venereal disease is negligible. It is true that there is a risk of infection with a fungal disease (one of the common venereal diseases), however, if the situation has already occurred and you do not feel disturbing symptoms - there is no need to implement prevention. If you start to feel itching, burning in the vagina or observe a change in the consistency or color of vaginal discharge - then antifungal treatment should be considered, preferably after consulting a gynecologist. I attach links to helpful entries: https://www.gdziepolek.pl/artykuly/jak-nie-zarazic-sie-choroba-weneryczna https://www.gdziepolek.pl/kategorie/grzybica-miejsc-intymnych