He was just pretending. Trying to figure out whatz up since he knows there is something cooking between Sona-Rohit. He wanted the dirt to add spice to it.
The last bit where he said 'now I understand what you mean by the Parvati dialogue'. Now he knows why Sona has turned into devdas.
Now he will maaro mauke pe chauka.
But though I knew Kunal was faking it, if it had been real, the scene wudve been nice. But Kunal is a totally bigda hua ayyash. He will now create problems between Sona, Rohit and use Raima for this.
Also, its just lust for Raima. He even fell for a cross dressed spot boy during Rohit's prank for god's sake𤣠Kunal will go for anything in a skirt.