She let's you end it.

"Sweetie I can't get balls deep at this angle, If I unlock you will you be good?" You needed her entire cock in you immediately, that's how you could cum, that's what you needed, you nodded vigously. "Yes! Yes! Please just let me have it! I need it all!" She goes to undo your restraints and as soon as you're free you assume a position on your hands and knees "I need it... please." She relubes her cock and places it at your entrance, she barely even penetrates before you thrust back forcing her whole eight and a half inches up your ass, causing you both to moan loudly. You're done playing games, she said she had to go balls deep to let you cum? You keep thrusting back and forth on her girlcock, bottoming out every time, you needed to cum. You feel her hands on your hips pulling you onto her, you kept thrusting, you were going to get what you needed. You begin moaning, nearly screaming, "Yes! More! Just like That! Oh god don't stop!" You couldn't stop humping back at her, if you stopped, you couldn't cum, you needed to keep going. You couldn't tell how long this had been happening but while she was ramming her big cock in your ass you felt something in your stomach, a warm glow, a euphoria, that moved down and... and. You scream "oh god Yes! Yes yes yes yes! Fuck my ass and AHHHHH" you unleash the biggest orgasm of your life, spraying the sheet under you. Flaccid and completely spent you keep pushing back against her cock, don't...don't stop, keep fucking me... Please.. keep fucking my ass..." unfortunately your pleading was just what she needed to send her over the edge, you feel her blow her hot seed in your ass and you can't help but love it. You can't stop pushing against her until she finally goes too soft to keep on going. you colapse in disappointment for a while, both of you lay in silence, cooling down until.. "So.. You don't wanna be assfucked?"