She wanted him to fuck her in the ass so badly but didn't know how to get him to. She wanted him to take it, to claim her. She fantasized about it constantly.
Sometimes she fantasized that he did it gently, easing her into it with a back massage and a lot of lube.
Sometimes she just wanted him to surprise her by slipping into her ass as he took her doggystyle. He'd pretend it was an accident and she'd pretend not to like it as he couldn't help but finish inside her.
She didn't expect it to happen the way it finally did. When she was nearly passed out on the bed after a night of drinking too many cosmos. He finally made his move when he thought she wouldn't remember. But even though Ali was indeed awake, she never let on that she was...until she could hide it no longer.
He entered the room silently and undressed completely before climbing into bed behind her. Ali had nearly fallen asleep but was suddenly excited by his warm body. She sighed sleepily and snuggled back against him. She had torn off her dress on the way to the bed and only her hip hugging cheeky panties remained.
He felt the smooth satin material on his cock and unconsciously pushed forward, "Mnnh," he moaned as he realized how horny he was. He reached around to play with Ali's tits, hoping to rouse her into letting him fuck her. After a few minutes of tugging and pinching, he received no response.