"But if the reading wasn't strictly higher than his high that day with Nicole, then I'd say:"
"'Sorry, but we'll have to work to get you more excited before I can let you cum... I don't want to be jealous of how much Nicole turns you on!'"
"We'd take off the hardness meter, and then I'd kiss him some more, sometimes with his cock inside my pussy! He wouldn't be allowed to cum until we measured a reading that was high enough, so just when he would get as excited as possible, he would be forced to pull out and hurriedly put on the hardness meter to get a reading..."