buckle up buttercup 

Buckle up Buttercup is a sarcastic expression, denoting that one should get ready for some upcoming unpleasant or extreme action.

It is a bit of a sarcastic portmanteau between the "buckle up" phrase used to get people to use seat belts and "pucker up buttercup" meaning to prepare for a kiss. The sarcasm reverses the positive connotations.

Buckle up Buttercup, you just flipped by Bitch switch.

buckle up buttercup by TheKnightWhoSaidIckyIcky October 17, 2018

Buckle up Buttercup 

Said sarcastically to those whom know your rules for riding Shotgun in your vehicle. Also for those nondrivers. Protect your points!

Me: After being placed handcuffed in the background seat of a patrol car by the Officiating Officer: "Excuse Me Officer, I see You and Your witness both buckled up when You entered the Vehicle, but You did not buckle Me in. Now I tell My Children to Buckle Up Buttercup when riding in My vehicle, and if I did not have You buckle Me in that would be a bad Mom of Me now wouldn't it?"

Buckle up Buttercup by ~Mask January 10, 2019