How does one properly tuck in a dress shirt (button down)?

Just tuck it in, nothing too special here. Make sure the bunchy parts are evenly distributed, and it’s a little less bunchy in the front that anywhere else. You also want it tucked it tight – don’t pull it up at all to make it looser – you want to avoid looking ‘poofy’.

good luck :)

I usually follow the same advice, but since I’m a bit ‘rotund’, I do a stretch after tucking and fastening, by reaching with my arms above my head…sound awkward, but helps to keep it ‘natural’ and just a bit ‘poofy’. Oh and don’t tuck into your undergarments-the shirt should be between the pants and the boxers/briefs, unless you fly ‘without a parachute’ (sorry if that sounds lewd!)...

Militarily speaking, you want a straight line formed by the shirt front, your belt buckle and your zipper. What I mean by this are the parts of the shirt and zipper than are the “flaps.” (This is called a gig line.)

Also, in addition to tucking your shirt in tightly (within reason), you can get a more uniform appearance if you grab evenly whatever is billowing at the sides of your waist/hips. and fold that extra material (usually and inch or so) toward your butt. The spot where you make those folds should be at belt level or just below, so that they stay put.