I used to rub my genitals in the border of the toilet seat ( i feel really ashamed while writing this) but not in public bathrooms! is is possible to catch an std with this way of masturbating? ( hpv in the cervix is my concern) p.d: i'm virgin?

Get a vaccine: Very unlikely to catch HPV from masterbation - but it all depends on toilet seat. At home? very unlikely. Public seat? Perhaps. Sounds to me like your worrying more than you need to. Why not get HPV vaccine and be entirely protected against HPV? (Still prone to other sexually transmitted disease from public toilet - uncommon but not impossible)