Fuck her?

You climb up onto her shoulders. Since she can lift you and that weight in front you figure you won't damage her. You swing one leg over her flagpole, then perch atop it. It bears your weight without issue.
"Daddy, what are you doing," she asks as she pats your butt.
"I have to deal with this, right?" You spread your legs and you guide her hands to spread your cheeks apart until her cockhole is pressed against your butt's.
"Daddy! You are just supposed to aim me so I don't make a mess everywhere, like we always do! Besides, how are you going to fit my cum in there? You know how much I make. You feeling well? You aren't making any sense."
That doesn't stop her from sliding her hands to your hips and pulling you down. You have used some sizable toys before in preparation for today, but she is going to reteach your ass what 'big' means! You relax your ass as she pulls harder.
"Once my hole is at your eye level, see how it looks impaled by your cock and then let's see if you tell me to stop," you tease her.
"It's going in! Well you did take Mom so I shouldn't be surprised. It feels great! No wonder..."
"No wonder...?" You look back at her.
"No wonder Mom says she likes your behind so much!"
She fully penetrates you, and you let yourself slide down her shaft. After the head, you can't tighten enough to slow your decent anyways. She stops you at her eye level.
"It looks amazing! You can stretch so wide! I could stick my leg up there!"
"Your leg isn't spongy at the widest part," you remind her.
"Ah, right. You are right," she says as she lets you slide down until you sit on her tits. It snakes through your insides pleasantly. "So how are you going to fit my cum in there?"
"Just by being receptive," you lie. The FAQ from your order confirmation said that you could take as much cum as you felt comfortable with, and they would stop when you told them to.
"But Daddy, I can feel my thing bulging out your belly! Where is it all going to go..." Abby ponders while running her hands over your body.
"Why don't we find out?"
You raise yourself a bit and lower back down, then repeat. Abby seems **** at first, then assists you.