The following advice is aimed at adults who have been dating for a good decade already.
In my opinion, you should do whatever you want with dating in your twenties, within the bounds of treating people with feelings like you would want yourself to be treated, of course.
The most common characteristic is a tightening in the stomach, the very feeling that gave the phrase its name – like a hundred little butterflies flapping around your stomach, almost nauseous, almost feverish, almost euphoric...
Your heartbeat is raised, feeling anxious, hopefully still excited, a buzzing in your ears, a dry mouth, you swallow to try and catch your breath - this is the elation and agony of the early stages in dating.
Further, this emotion fades relatively quickly, and does not predict whether a couple will have a loving and successful marriage.