Idiom:

Play by ear ( do whatever you want without plan )

Hit the book:

Stimulant

Inhibit

Torture

Symptom

Quit drinking coffee

Coffee contains caffeine that will prevent you to sleep, so that you will suffer insomnia (sleeplessness / not getting asleep). "Caffeine is a stimulant, and inhibit sleeping," said David C.Brodner, MD, medical director of Center for Sleep, Allergy, and Sinus Wellness in Boynton Beach, Florida. Caffeine will stay in your body in a period of time, and it will lose in approximately 6 hours after you drink coffee. Therefore, you should avoid drinking coffee 9 hours before you go to bed.