As soon as Aria has gone tipsy, maybe, due to the fizz of the soda and the urge to stay close to another human being, she had gone way out of control as possible. Aria doesn't know what she should do, but his lips rolled inside her mind, and when she thoroughly moved, he responded.
Prince didn't know how he gave in, it just happened. It must be crazy to think that he's kissing the one he plotted to kill, making her fall in love, as if it's natural for them to have a connection within days of being with each other's side.
He traveled his fingertips around her waist, letting go of the soda can. He pulled her closer, deepening the kiss.
This is a traitor act. Something that Bryce would lash out if he ever find out.
Prince made out with Aria, and no one should even know who initiated it.