(do something) like it's going out of style
To do something very frequently, quickly, or in great amounts. My husband took a baking course last week, and now he's making cupcakes like it's going out of style! After getting his bonus, Jim started spending money like it was going out of style.
do something like it's going out of style
or do something as though it's going out of style
If you do something like it's going out of style or as though it's going out of style, you do it a lot and with great energy. My grandkids eat this dish like it's going out of style. These footballers have been spending money as though it was going out of style.