Weirdest experience in Delhi Metro? I'll go first..

This one is... I don't even know how to describe it.

The day before yesterday, I was travelling by Delhi Metro to my Maama's place in New Delhi and I was sitting quietly minding my own business. There were a couple of seats empty right next to me, so a young couple(?) sat next to me. I was too busy to notice as I was watching some shit-ass third rate Korean movie on my phone. Suddenly the girl elbowed me kind of hard on my ribs so I paused the movie and the girl apologised to me normally. So far normal, right?

I was a little surprised at the sudden jab at my ribs but I shrugged it off as her being careless and minded my own business, I was about to resume my movie when a strange voice caught my attention. It was a baby like voice which was coming out of, you guessed it, the girl sitting next to me. She was talking to her man in a baby voice. At first I thought she was being cheeky and playing with her bf but being the nosy guy that I am, I was eavesdropping, for full 2 mins she was going full on baby voice mode; then suddenly the both started interlinking their arms and intertwined their fingers, at which point I started dying of cringe at her voice. I looked in front and saw an older couple staring at them with abject horror on their faces also cringing at the couple's shenanigans. When she apologised to me, woh apni normal awaz mein bol rahi thi. Bhai yeh kaisi fetish hai ki bachche ki awaz mein baat kar rahe thhe.

IK it's not my place to say anything or judge them by any means, but can you blame me for finding this funny? And before anyone asks, both the guy and girl looked well into their 20s.