Consent to Flirt?

What does consent to flirt even mean?

It means throwing something out there and seeing if it's welcome or not. If they reject your advance, they don't consent and you move on. If they welcome it, they consent and you may carry on. They or you may revoke consent at any time.

Is there a difference between flirting and seduction?

Flirting, as mentioned above, has no serious intent. Seduction has intent for sexuality.

Who decides what is flirting, what is merely being friendly and what is full on seduction?

The person or people that are flirting. Initially it starts with one person, then both are engaged in the exchange. If you can't read the intention or want more clarification, ask. If you are asked, be truthful. If the exchange continues, it should remain at the "slowest" person's pace and not move until they've given consent to shift gears. Do not expect it to shift gears if someone says they are merely flirting with you and you want to seduce them. If you're not interested in only flirting, end the exchange, preferably with love.

If the intention of seduction is to have sex with someone, what is the intention of flirting?

To boost your ego and someone else's ego. Case in point, people who spend time on Bumble and Tinder with no intention of meeting people.

Is there anything wrong with flirting?

No, as long as everyone is consenting to it and understands the intention and meaning behind it.