Kurt and Rachel are watching Quinn and Santana who are isolated on a sofa in the corner at a party.
Rachel not seeing very well then asks. "What are they doing?"
"Santana is doing an experiment." Kurt replied factually.
"What kind of experiment?"
"How far her tongue can go down Quinn's throat." He replied laughing when he saw that it was getting hotter and hotter between them, and that Rachel was blushing amply. "I think they're in heat." He continued.
"Oh my god, Kurt! Of course not! They are not animals." Cried out Rachel, horrified.
"Well, they clearly fuck like ones. Have you heard them last time?"