my girlfriend and i were fouling around on thurday night and I masterbated on the crotch of her pantyhose while she was wearing them without panties on can catch anything like and std by doing that?
For the most part NO > you would not have the degree of direct contact with body vaginal fluids to catch most such as gonorrhea, chlamydia or HIV... I suppose remote and very unusual possibility if she should have problems such as pubic lice or an active superficial herpetic ulcer... these would be VERY unlikely scenarios so unless you have symptoms I think you need not worry due to this encounter!!
I hope that this helps. Let me know if you have further questions and I will be happy to get back with you! If my answer has been helpful and to your satisfaction then please remember to leave positive feedback. Thank you and Best Regards,
Anthony Bray MD