he would place it behind his ear. this flustered alhaitham, as the exchange of a feather is considered to be a sign of a very close relationship between two people, but kaveh refused to part with it, and would wear it everywhere he went.
for some context, in this wings au the teal feather kaveh wears in his hair is something he got during his akademiya days, it’s one of alhaithams feathers.
while alhaitham was going through a phase where his wings were growing faster and gaining their distinct colours, a few feathers would fall out as his body adjusted. kaveh once picked up one of these feathers, and while teasing alhaitham about how ‘his junior is growing up’