how do I know I orgasmed?

Naomi • Livin' the single life

I think I've never done it... I just don't know. In porn (I know that shit is fake but it's an example) the women cum and it overflows and spills out. Does that happen every time? I feel like I orgasmed last light but I definitely didn't feel anything extra come out and it only lasted a few seconds :/ it was pretty great though. How did you know when you first orgasmed?