I'm a skinny person and everytime I try to ruck my shirt in my pants, it makes me loot fat.
What am I doing wrong ? Seriously I saw videos and tutorials but I suck at it
If you're wearing an undershirt that's probably the problem. Tuck your undershirt into your underwear then your button up into your pants over your underwear. It creates a cleaner profile and front. Also, you can military tuck.
I usually wear a t-shirt under my shirts.
Military tuck is about "pinching" the side parts and folding them ? I'll practice this one too.
I'll get to the tailor when I can. But I don't see the point tailoring a shirt of the smallest size I could have and that I paid 20€