Green’s Dictionary of Slang

tweeds n.

1. (Aus./N.Z.) trousers.

[Aus]Advocate (Burnie, Tas.) 5 June 7/2: ‘Some tweeds, Browney,’ ‘Look at the crease in his strides’.
implied in drop one’s tweeds
[Aus]D. Ireland Unknown Industrial Prisoner 2: Drop your tweeds. Cough. He wasn’t paid to look for nervous disabilities, just cripples and dead men.
www.xenoxnews.com 13 July 🌐 Stand on their lawns. Then drop your tweeds, squat, and deposit something worthwhile on their glorious garden.
[Ire]P. Howard PS, I Scored the Bridesmaids 174: I whip up the old tweeds.

2. (US campus) a suit.

[US]Baker et al. CUSS 215: Tweeds. A suit.
[US]E. Grogan Ringolevio 77: Believe me, take ‘tweeds’ and forget the ‘threads.’.

In phrases

drop one’s tweeds (v.)

to have sexual intercourse, lit. to remove one’s trousers/underwear.

[Aus]A. Buzo Norm and Ahmed (1973) 21: Pervs aren’t choosy, you know. Some of these blokes’ll drop their tweeds for a ripe banana.
[Aus]A. Buzo Rooted III i: Susan was a lovely girl. She never dropped her tweeds for anyone.