Oof this is really cute
I can imagine Shizuo likes to tickle Izaya really gently and softly whenever they’re just relaxing and enjoying each other’s presence
Like Shizuo isn’t doing it to make Izaya suffer-really anything rougher than this is enough to make him suffer-he just wants to see Izaya smile
And Izaya doesn’t mind it
It’s just ticklish enough to where he squirms a bit but it does feel nice and it actually kinda calms him down whenever he’s not feeling too great
Sometimes he’ll complain and whine about it but they both know he’s just stubborn and embarrassed
There’s an unspoken understanding between them so whenever Shizuo does it, Izaya doesn’t put up
much ofa fight and Shizuo doesn’t call him out on it