Green’s Dictionary of Slang

sexual intercourse; esp. in the phr. a bit of the other; usu. hetero- but sometimes homosexual.

1936		J. Curtis Gilt Kid 135: ‘Doing half I was.’ ‘What for? The other?’ ‘Yes.’ The pansy simpered.
1959		W. Hall Long and the Short and the Tall Act I: With three or four nippers howling out for grub they don’t have time to think about the other.
1967		J. Orton Diaries June (1986) 273: The people here leave a lot to be desired and flaunt their preferences for what they cryptically call ‘bits of the other’ at every cafe .
1976		P. Theroux Family Arsenal 71: ‘I’ve tried sleeping pills. They don’t work.’ [...] ‘Bit of the other, eh?’.
1982		P. Bailey Eng. Madam 95: They’d be around for a bit of the other even if it meant struggling through a bloody snowstorm.
1989		M. Amis London Fields 112: Some women didn’t like otherness; they didn’t like the other, when it came to the other.
1996		J. Cameron It Was An Accident 29: Be a bit better for a bit of nookie though, touch of the other.
2004		P. Howard PS, I Scored the Bridesmaids 123: We haven’t had a bit of the other [...] since we got engaged.
2013		T. Black ‘Daddy’s Girl’ in Killing Time in Las Vegas [ebook] I liked two things, playing the ponies and the other.
2016		Guardian 13 Aug. 🌐 I was intrigued to hear that, for a while, Trotsky had made a habit of nipping to the nearby home of the artist Frida Kahlo for what unreconstructed people would call a Bit of the Other.