How do you pull off a shirt+t-shirt combo? Plenty of people wear

Buy slim cut shirts that are otherwise too short to properly tuck in. Like in your pic, there is barely 2-3 inches of fabric to tuck on the sides.

>>18548263
Basically this

Make sure you are getting casual button ups that aren't meant to be tucked in. They can be distinguished by their shorter length, basically they are the length of a regular shirt. If the wind starts picking up just button it up until the wind dies down.

>>18548036
why don't you want your loose clothes to be flowing in the wind? a lot of designers make it that way on purpose