Angry or amused?

Just what you did, they hate being ignored.

Definitely ignore. Turn your back and find something interesting in the cafe. I blame the parents

Having never seen that gesture ( I live a sheltered life)
Not sure how obscene it was, but think I would have shook my head pityingly at them and gone back to reading the paper.

I'd probably go back to reading my paper whilst I slowly gave them the middle finger.

Ignored them.

I like to be tucked up safely indoors when the school kids are about.

I remember a child doing that at school! Last day of term and handing out ice lollies to the class, and a particularly obnoxious child started doing it to his lolly. Luckily he was seen by another teacher who whipped the lolly out of his hands, so he went without. Serve him right, I'm afraid.

I used to work as a car valeter, we had the massive windows car show room windows.

A young lad (prob start of secondary school used to walk past making gestures

But one day he was saw engrossed making the gestures he forgot about the Lampost!!! ha ha ha lol Oh !! revenge as they say is best served cold lol. "Smack" right into the lampost. lol 40 yrs later I can still picture the scene lol

" so" engrossed not saw!

Ignored them, they thought they would anger or embarrass

I’d have ignored them.

I would have ignored them, but sometimes a reciprocal gesture has a shock effect.
My ex father in law, who thought a woman's place was barefoot and pregnant in the kitchen, was always giving women drivers a mouthful of foul abuse, until the day a smartly dressed woman in an expensive car simply stared expressionlessly at him then gave him a V sign and drove away.
He was speechless.

Best thing is ignoring them as most have said because the airheads are only waiting for a reaction and when that's not forthcoming they'll just go on to the next one, or give up altogether. Let's hope the next one gives them a fourpenny one !

I have no idea what you mean but I can guess.
Poor deprived souls, they can't be living very interesting lives if that sort of thing amuses them.

I suspect I'd laugh.

They hope to shock us old fogeys. Best to show that all they are is boring.

I would just fail to notice it, I have found that seemingly being unaware when someone is trying to shock by either making gestures or saying something that is meant to be shocking, rather takes the wind out of their sails.

Either ignore or an eye roll.

Perhaps repeat the gesture back to them, but just using the thumb and forefinger, indicating that they have a very small, teeny weeny penis! (To match the size of their brain)

I agree with phoenix - indicate that you think their penis is terribly tiny !

Reminds me of my sister who went out with a boy back in her teens - he suddenly whipped out his penis like a magician pulling a rabbit out of a hat. She had the presence of mind to say " Gee I'd need a microscope to see that ! "

I would be tempted to reply but know I shouldn't. But honestly, how times have changed! Disgusting!

missadventure?

I would ignore them, they could approach you and then you would feel threatened.
In our town a teenage girl was vandalising a building, when told to stop she pushed her face right into the face of the person talking and said "make me". I have seen the video, she was so venomous it made my blood run cold.

NO! What they want is a reaction. Any reaction. Don't give them the satisfaction. End of.