They tie you up and ride you

You wake up to a had slapping across your face. Based on how your face feels now, it probably wasn't the first slap either. As your senses return you realize a few things. One, you've been blindfolded. Two, you're wearing some sort of heavy gag. Three, you're laying on a bed face up with each limb tied to a bed post. Finally, you're wearing some sort of belt just above your crotch. You groan through the gag.

"Oh good. You're finally awake. Who knew two little girls could knock you out for so long" says one twin. The other one giggles and says "those krav maga lessons are so handy sometimes."

You struggle against the restraints. "Oh don't bother with that, you're our own personal toy for the night."

"Don't worry though, we are going to ride you all night like the slut you are"

"But don't worry, you'll have a chance to redeem yourself. If you can figure out which of us is which by the end of the night."

You try to protest but nothing comes through the gag. The girls climb on to you, one by your head and one by the belt. You know suspect that the gag is actually a modified double sided dildo and the belt is a strap-on. This is seemingly confirmed as each girl positions their weight over one and drops their hips down onto you with a moan. You can smell the sweet pussy of one over your face.

The twin on your face rides you slowly, and gently caresses your chest as she rises and falls on your faces. The twin on the strap-on rides it hard and forcefully. She slaps you and the sides and belly yelling "you're our bitch tonight!"

Time seemingly goes on forever as they both make use of you while you feel nothing besides the work of their hands and the slight feeling of one twin's butt rubbing next to your dick as she rides the strap-on in proximity. Suddenly, they both yell and seemingly cum together. You can taste the sweet nectar of the one as it drops down the double sided gag you're wearing.

"Let's switch!" Says the one on your face. "Fine" comes the reply.

They briefly get off and shift around until you feel each girl settle down onto their positions again. This time, the smell is a bit more bitter from the second twin. She continues to ride the dildo rough making you gag as it pushes down into your throat. She slaps your chest as she goes up and down.

The other twin has seemingly mounted you in the opposite direction. She slowly rides the strap-on but also plays with your cock and balls with her hands. She's obviously quite skilled as her soft hands feel like tender magic.

The twin on your face dildo cums quickly but doesn't stop. The other girl takes several more minutes but finishes and stops playing with your dick before you can finish yourself. They both dismount and stand next to the bed.

Without taking any of the gear off you, they ask "you don't get to look this time since that didn't help before, so, which of us is which?"