What does the term "milkshake" mean?

Question

My FWB sent me a text that had milkshake in it and I feel like I should know what it means but I'm lost.

Answer

Perhaps just a milkshake. However there's a food stand in Chicago known for its abrasive/borderline abusive staff that it's practically a part of their brand and appeal. Anyway, they deal with a lot of drunk people and they would chant "chocolate milkshake" to get the girls behind the counter to flash and ultimately "shake" their boobs. The place is called The Weiner Circle. Not exactly my cup of tea, but became popular among locals and tourists.

Answer

No he didn't mean milkshake as in the drink. I told him I'm obviously missing something and now.......Silence. 
I tried googling the slang meaning but it says it means SOOOOOOOO many things. I'm lost.

Answer

I hope it just means milkshake because I’m having one right now... it’s white too

Answer

'My milkshake brings all the boys to the yard'

Answer

Can’t help you unless you put it into context.