Blag

Comes from the old word "blackguard", a contemptible and untrustworthy person, which was pronounced "blaggard".

The sound of the last part "ard" became confused with the suffix "ard": meaning a person who does an action, as in drunkard. "Blag" becoming the contemptible untrustworthy action.

I first came across it as a teenager working on a building site nearly 50years ago, when an old Irishman accused another of "fucking blaggarding". I didn't know what it meant, but was obviously a bad thing to accuse someone of and not done lightly. These days it seems to have lost its former vehemence and is used more in the manner of petty criminals boasting of their offences.
"Where did you get that from?"
"Ha ha ha, fucking blagged it didn't I.

"Did your wife say anything about the time you got home?"
"Yes, I gave her some blag about working late."
by A handle not already used January 24, 2020
mugGet the Blagmug.

Pissed up the wall

To have spent money buying alcohol to drink.

Came across it c.50years ago when a teenager on a building site.
I think it may be where "pissed up" meaning to be drunk came from.
Foreman: "It's Monday and he asked for a sub, he got paid on Friday! All his wages pissed up the wall"
Me: "What's pissed up the wall?"
Foreman: "What? Oh, it's going out and getting drunk."
Me: ....?
Foreman: "Staggering home they'll feel like a piss and go against the nearest wall: what they'd spent their wages on just gets pissed up the wall."
mugGet the Pissed up the wallmug.