He gives in

It was as if he'd lost control of his limbs. Drunk with the heat and the taste of wine in her mouth, he reciprocated her affection by getting a good feel of her ass. He let her slid her tongue inside. She explored him thoroughly. Her tongue was making his manhood rock hard, to the point that it almost hurt him to have his pants on.

Once she had apparently enough, the lady ripped open his vest exposing his chest. She kissed it and then started to lick his nipples. Bran enjoyed that and his hands slid up her body, feeling the soft skin of his hostess. Her hands undid his trousers and his cock sprung forth, relieved to be finally free of those pesky clothes.

Melisandre stopped for a second before saying.

"Enjoy this well, milord." The lady then got on her knees and started sucking him. The young lord inhaled sharply as he felt her warm and moist mouth envelop his cock. He watched with pleasure the mop of red hair go back and forth his shaft. Her tongue swirled around his length, but Bran felt a chill up his spine once she started teasing his sensitive tip with it. The profane sound of her lustful slurping filled the room along the occasional grunt that the Stark let out.

Melisandre upped her act by going all the way to the base of his manhood. His tip was reaching what it seemed like the back of her throat and Bran had to restrain himself from emptying himself inside of her throat. Up until then, the young lord hadn't truly known how it felt to really be with a woman. Melisandre and her mouth brought him more pleasure than anything he had tried before. Was that what he was giving up when he had rejected Meera? A 'pop' sound came from where the red woman had been sucking. His cock felt cold all of a sudden.

Whatever it may be, Meera, Sansa, Arya and everything else was a distant thought at the moment. What mattered was Melisandre and the obvious prize between her legs.