So I just realized that there is a sport called Double Luge

What is the purpose of the person laying on top of the other even?

Brutal finish

Here's an interesting fact regarding the double luge from and NBC article:

For 62 years, doubles luge was a discipline solely competed by men at the Olympics. It was added to the Olympic program at Innsbruck 1964, in addition to the men’s and women’s singles events. And for decades, female athletes did not have the chance to try their hand at doubles on the world stage.

So the luge people were like "No women allowed only dudes who get to sit on each others lap going down a track 77 mph"