They both failed

"You both failed then?"

The twins both gulp before nodding silently.

"Well then, time to see who lost the competition and will be getting punished."

The twins both look down to the ground with fear, of course uncertain of which of them orgasmed more throughout the day since it would all have been a haze to them.

You pull out your phone and check the app connected to their heart rate monitors. You had it set up to count the number of events in which either of them reached a heart rate elevated to high enough levels to indicate an orgasm.

"Let's see what we have here. Looks like the winner is Tracy, with only two orgasms, beating Mia who had a whole four."

Tracy lifts her head with a smile, whilst Mia looks at you with a face of fear.

"Well then, time for your punishment whore. Both of you follow me to the basement."

With that you switch off the TV which is now showing a scene towards the end of the twins' gangbang of Tracy swallowing a large volume of cum from Mia's ass.

You then head towards the basement, with the twins following you on all fours.