How I saw my male friend naked

[Freesub]

This is a story of when we were in 7th or 8th grade, and I was over at his house for some reason which I do not remember.

Regardless, he had left the room shortly before as his mom called for him and I was busy playing with a ball.

The ball happened to roll down the hallway and into the room at the other end (it was a short hallway)
So I walk in and find my friend standing on the bed, stark naked, waiting for his mom to find his swimsuit from the cupboard.
I do not know why she had him strip naked before taking the swimsuit out, but regardless, I saw pretty much everything as she turned around to shield his front against his mom, showing only his butt.

His mom just laughed it off saying "It's only Freesub" and made him turn around and wear the swimsuit in front of me (exposing everything again)
It was too loose or something and she told him to take it off, and I felt bad for him since I knew what it felt like to a have a mother who disregarded your potential embarassment at being naked, so I turned around and left while he was taking it off again.

I'm only attracted to girls so it wasn't that exciting for me, but it was quite amusing and something to tease him by.

We didn't say anything about it at the time, but a couple years later we were able to comfortably joke about how I saw him naked.