Masturbation for a Beginner (sort of)

So I have been doing the deed since around high school, BUT I think I just do clitoral stimulation through my underwear(?) That's been fine for me mostly, because I don't much care for the cleanup aspects of the other options. However, I'm feeling like I need to venture further despite that discomfort. I don't use tampons because the friction from removal burns, and I'm also a virgin. Any advice for a transition plan to more involved madturbating? I just don't know what I'm doing, and I'd like to get over the discomfort of bodily gooey-ness.