Back when I was 16 I cycled a bike off a bridge into the river below and just acted like it was the most natural thing in the world to do (in front of a girl I fancied). That was very cool though she still didn’t want to be my girlfriend which was her loss.
How about you? 
Held my newborn son in my hands for the first time.
lol
nah just kidding. probably when I flipped a bottle cap across the room and it landed in someones glass.
was there a build up/ dare involved? Or did you just cycle straight past her into the river with no warning?
were you clothed?
I’m not sure this was as cool as you think it was 
One time when I was maybe 17 and really pissed at a house party, I reckoned I could throw a wet ball of kitchen towel from the back steps into the bird bath in the middle of the garden. With my left hand.
Somehow managed it on the first attempt, which impressed my even more drunk friend so much that he insisted on paying me £1. We hadn’t made a bet, he just felt that a feat like that deserved compensation.
I later pissed in that bird bath, and for that I am still ashamed.
I once pulled off a very difficult pool shot in a crowded pub and it wasn’t a fluke or anything
Being good at pool is intrinsically cool
Playing air hockey against my brother on a family holiday (I was probably around 13/14 at the time), he hit the puck so it was basically bouncing manically back and forth between the sides of the table around the half way line so I flung my paddle at the puck and caught it so sweetly that it fired stright into the bottom corner to audiable gasps from the few people around the table who were causually watching.
played it pretty cool I think Bam
probably moved on to the next shot like it was no big thing
Nice right hand barrel on a 16ft wave, followed by a 360° spin, when bodyboarding in Hossegor. Was glassy as and a decent off shore breeze to help form the barrel
