"Get a grip" means to control yourself, as if you were hugging yourself tightly to prevent loss of control. A double grip would just be an interesting way to tell you to be extra controlled.
"Get a grip" is an idiom that means to gain control of your emotions or behavior, to get ahold of yourself, or to start managing a situation better. It can be used to encourage someone to focus, become more rational, or take charge of a situation.
calm down and get a grip on your emotions.
Don't take an action that will result in harm to yourself that you did not intend.
If you "get your hands dirty" figuratively, you're willing to do the work yourself.
It originally came from cotton farming, and means to do an entire job by yourself.
"Have at it" means "give it a try". Another similar colloquialism or idiom would be, "Go ahead, knock yourself out", or "Go for it".
Whistling in the dark means you really don't know what's going on are trying to comfort yourself.
Do you mean a vice grip?
It is not an idiom, it means your nose is itching.
It's not really an idiom. It means "what are you thinking about."
RFP is not an idiom. It's an abbreviation.
Nothing. However, a brown bag LUNCH means one that you pack yourself, usually carried in a paper sack.