What Are The Chances Of Pregnancy Through Non-penetrative Sex?

Question: I had a question regarding pregnancy risks. My boyfriend and I were fooling around Sunday night, but agreed to not have intercourse (we've never had intercourse before and I've never had intercourse ever). That being said, we were "handsy". I briefly grabbed his penis (not the tip) before putting it back away (unsure if he ejaculated or not). When he went to wash his hands, I did not wash my hand. He gave me the towel he used to dry his hands to me to at least dry off my hand. Even though we'd both been wearing our undergarments, what is the likelihood for pregnancy in this scenario? I'd only laid out my hand on my side before "cleaning it", and there was no penetration going directly into my vagina. That being said, I had concerns just in case I did have semen on my hand, and with my period planning on coming within a week, I wanted to know the risk I'd put myself in for pregnancy? I'm currently off my birth control pill (for cramps) and have no desire to get pregnant. I realize it sounds like a ridiculous question given that I've learned about sexual health through school, but I did have some concern given that my personal experience is limited. My partner and I have discussed engaging in protected sexual activity and the risks it brings should we go into it gradually. If you could clarify the potential pregnancy risk with further information, I'd greatly appreciate it.