In the past, I've commented that I'd like to see shorts and slacks with a bead of urethane inside the waistband to prevent shirts from un-tucking during the round.
Until that happens, I have found a solution in Hot Melt Glue Guns. Mine has a high temperature setting that allows the glue to somewhat work its way into the fabric and not wash out. It doesn't take much glue and, if your shirts tend to un-tuck during your swing, this solution may work for you.
To apply, heat the gun and draw a bead about 3 inches long in the front, inside waist band. Then, allow it to cool completely before hanging, folding or wearing the garment.