An outfit check

[Highland Logan]

You had me wondering there, I always defined "blousing" as adding fullness or looseness -- and Dictionary.com agrees with me:
intr. & tr.v. bloused, blous·ing, blous·es
To hang or cause to hang loosely and fully.

Agreed. When we usedd to "blouse" our trousers in the Army, it was just as you discribed.

Frank