How do I talk to my girlfriend about ?

So im nervous about talking to my girlfriend about and things of ual nature .because we have made out multiple times and I fingered once, groped on each other and I afraid to talk about these things we done in the past. Like right after I got through her we'll start talking about tv show or someting as if what we did never happened.We never dicussed the ual things we do each other and lately i've been even more pressured because her closest friends tell me I should talk about "freaky stuff" because she according to them she's a freak herself. But really I don't want to talk about actual I just want to talk about what pleases her the most Like what turns her on and what are her boundaries and have I been doing a good job and stuff.So how do I go about bringing up this topic ?.