Bovril bypass, n. — Green’s Dictionary of Slang

Bovril bypass n.

also Bovril turnpike

[for ety. see Bovril n.; the association of the anus with the colour brown]

the anus.

2002		gubbins69 🌐 I wouldn’t even use that stuff to moisturise my bovril bypass, its crap. there are only 2 surefire ways to remove those pesky wrinkles and they are both far more natural.
2024		J. Meades Empty Wigs (t/s) 617: Tronk was piss and slopping out [...] being held down by Lag A so that Lags B, C, D [...] could travel the Bovril Turnpike.