The Fit Boxy relaxed fit, sits just on below the waist line...Not designed to be tucked in. Go for 1 size down if you want a more fitted look.
 
Details
Fabric: 86.2% cotton, 8.6% viscose, 5.2% polyester / 120GSM
Fabric Weight: 3.5 oz/yd² (120 g/m²)
Mid-weight 2tone plaid
 
Care Instructions: Machine wash at 30°C (gentle cycle); Do not bleach; Tumble dry low; Iron at low temperature, avoid ironing on print; Do not dry clean
Size guide (CM) - Model 6ft wearing medium. Usually wears M/L.