Underworld Slang: "The Lamster"

No, it's not a story about a cuddly rodent, it's another excerpt from The New Yorker's series about "underworld slang." Once again I leave the translation up to you.

A shaum I knew came over one day and told me the beef was in. My partner figured the rumble was too hot and to square himself he fingered me. I tried to connect for a roscoe but missed. Anyway, I went out to tamp up this partner of mine. I found him in a gin-mill playing Santa Claus for a couple of blondes. The dive was crowded but that was no hold-back for me. I declared my weight to the guy and called him a fink and then asked him to step out. He had to go then and right hands was trumps. I got this shiner for my end but I put him out of the picture. Somebody hollered "Jiggers!" and I lammed out the hammer and tack.

(This is from the April 21, 1928 edition).