Yesterday I did some penile rubbing not on vagina but on pubic hair around and above it on skin for 2-3 mins before doing protected sex, what are the chances of catching any STIs from this act ? Really anxious right now.
No, there is no risk from rubbing there unless she had a sore. The skin there is too thick to transmit anything she might have unless she had a syphilis sore or herpes sore.
You can use oil so long as you aren't going to use condoms. Oils can break down latex condoms. If you are going to use condoms, use a water based lube instead.
Also, talk to your partner before using anything to make sure she has no allergies or sensitivities to whatever you use.