The information you were given was incorrect. HIV is not spread by your partner rubbing her vagina against your scrotum. You did not penetrate her in any way and your exposure to her secretions was minimal. Thus this exposure is within the realm of masturbation which is safe sex. No risk to you for acquisition of HIV or any other STD. Please realize that in the course of masturbation miniscule amounts of genital secretions are inadvertently shared between partners, nonetheless there are no HIV transmissions which have occurred in this way, not ever.
In addition, it is probably worthwhile to also point out that the chance that your partner had HIV is also very, very low.
Bottom line, putting g the two facts I’ve mentioned above together, the exposure you describe is no risk and does not warrant worrying or even testing. Put this experience behind you and move on. EWH
i found this very helpfull :) thanx