Green’s Dictionary of Slang

wee adj.

SE in slang uses

In compounds

wee man (n.)

(Irish) the penis.

1998

P. McCabe Breakfast on Pluto 24: Inserting one’s wee man into these rasher-drying ladies — well, it simply wasn’t on.

wee small hours (n.) (also wee-wee hours)

the very early morning.

1849		C. Brontë Shirley II 73: She followed the steps of the night, on its pathway of stars, far into the ‘wee sma’ hours ayont the twal.’.
1902		J.H.M. Abbott Tommy Cornstalk 172: Bloemfontein we came to in the ‘wee sma’ ’ hours of the next day, and were immediately taken from our trucks, given a drink of hot milk and bovril, and placed in the bell-tents of the big canvas hospital.
1975		L. Rosten Dear ‘Herm’ 83: He [...] gets her home way past the wee-wee hours.
1989		T. Blacker Fixx 207: Discretion flew out of the window in the wee small hours.
2009		C. Ternan On the Back of the Other Side 53: Slowly, somewhere in the wee small hours her mind began to turn towards practical things.
2012		H. Fairman Ghosts are Real 45: She had suddenly awakened during the wee small hours, around 3.00 am.

In exclamations

wee buns! (also wee onions!)

(Ulster) no problem!

1988		S. Belfrage Crack 385: The fearless Provo woman who was once caught carrying two .45s [...] Her attitude about the prospect of a fourteen-year sentence was ‘wee buns’ (No problems).
1994		E. Macnamee Resurrection Man 126: ‘Still,’ he said, ‘you handled him well.’ ‘That class of a man's easy. Wee buns’.
1997		Share Slanguage 305/1: wee buns/onions [exclam.] (Ulster) No bother!
2003		S. Millar On the Brinks 171: Shouldn’t really be any problems, though. Wee buns.
2011		H. Hamill Hoods 121: The specific deterrent effect of prison on those imprisoned diminished over time with each sentence. For example, Joe (age, 18) said, ‘It's wee buns in here’ [Hydebank YOC] .