Think about Magnus and Alec in the shower.
Bodies wet, lathering each other with their fancy soap.
Shampoo falling into Magnus’ eye, and being a big baby about it, so Alec has to help him rinse it out.
Alec thinking that Magnus is dumb and can’t stop laughing at him.
The two of them get out of the shower and dry off, but Magus hits Alec in the back with a wet towel. Alec tackles Magnus, and they slip onto the floor.
And they laugh like idiots. Perfect, wonderful idiots.