You aren’t sure.

“I don’t think I’m ready for that. I’ve never had a cock that big, let alone a knot.” You loot at the floor.

“Awe, you cute silly girl. I’ll take care of you. No sweat, easy peasy. Hop on the bed I’ll get my explorer box.”

You slide onto the bed. She locks the harness in place, skips over to another cabinet, and pulls out a big black box. She scampers back, gleaming. “Ok, let’s start so you can see everything. Put the pillows behind you so you can prop up, then lift your legs as far as you can, spreading them.” You do, your feet touch the bed frame. “Is that comfortable?”

“Ya, but holding my legs up like this will probably get tiring.”

“No problem.” She takes two pieces of soft silk rope and ties your ankles to the bed frame. “Better?”

“Ya, I guess.”

She rubs your cock, “Well your dick is certainly enjoying it. Look how hard you are, my sweet Lexi.”

“Ya I guess… oh wow… um…”

She takes a bottle of creamy lube and starts squirting it into your ass, while using her dainty long fingers to drive it in farther. “Oh neat. You are really stretchy. You’ve got a nice little super power I think. Elastic ass woman.” She laughs till she snorts, “I don’t snort. Don’t lie.” You can’t help but laugh. She pulls some medical looking device. “Let’s measure it.” And basically just stuffs it in your ass, it’s so cold you yelp and a tiny spurt of cum hits her on the forehead. “Nice.” She licks it off then starts cranking, opening your ass. “Say when it hurts.” To your surprise, it never actually hurts, but she does stop eventually. She reads the device. “Well, you are going to be able to take any cock we throw at you eventually. Your ass is awesome. For now I think we should just go with…”. She heads to the case and grabs an almost glowing electric blue horse like dildo, clearly more than a foot long and thicker than her wrist. Not as thick as the big Flint, though. “This is 2.6” tapering to 3”. I’m betting it’s perfect. Do you trust me?” She asks wagging it at the foot of the bed.