lesbian shoes
Urband dictionary has this to say:
birkenstocks		
slippers for lesbians
The gym teacher wore birkenstocks to the sleepover.
4.	birkenstocks		
Those ugly uncomfortable sandels that lesbians wear.
OMG becky she is a dyke because she paid $60 for those fugly ass birkenstocks
birkenstocks	
Once known as ugly lesbian shoes, now the "cool" thing to wear.
Still ugly.
"Check out the dyke with the birkenstocks!"
"OMG Becca, I just bought these $80 birkenstocks at Abercrombie and Fitch!!"
birkenstocks		
Lesbian Prada.
That is, however UD insists on 20 letters and 3 words, so this is just filler.
Person A: She is wearing birkenstocks.
Person B: She must be a tuppence-licker.