improvise, wing it, play it by ear
Shakespeare used this in his play Julius Caesar.
It means someone is telling you a small hint to remind you of something
It can mean either you didn't pay enough attention, or you just didn't understand.
It means that you are going to seduce him/her. i.e when a guy says "may i blow in your ear" it means "lets go get busy (have sex)"
It means to get your full attention and listen to what he/she is going to say
If you listen to gossip, it will poison your ear about Joe.
The LITERAL meaning would be a flea in your ear! But "a flea in your ear" is an idiom, a saying, and it is not normally used literally.
You think about him. ALOT
If you have your ear to the ground, then you are listening to gossip or rumors, and you know all of the latest "dirt."
Vincent Van Gogh is said to have cut off a piece of his ear for a lover, leaving him partially deaf. So to say someone has "Van Gogh's ear for music" is akin to calling said person tone deaf.
Play it by ear. If you play it by ear, you don't have a plan of action, but decide what to do as events take shape. Yes it is 'play it by ear' and it comes from when a musician plays a piece of music without the music sheet in front of them, they are making it up from listening to it, playing it by ear.