Do you always know if you’ve orgasmed?

I started trying to masturbate very recently and I’m not sure if I came or not. A few times (about five minutes into starting I have gotten an AMAZING feeling for ten seconds or so that had me shaking and out of this world but I couldn’t chase the feeling and just ended up bored and unsatisfied after a while. BTW I’m using a DIY vibrator LOL.

Anyway how do you know if you’ve come or not? What’s a good way for a first timer to get there?