Green’s Dictionary of Slang

to love, to be in a romantic state; to ‘chat up’; thus turtle-doveism n., love.

1850		Lytton in Life (1906) I 25: A young clergyman and his wife, only just married, and in a state of turtle-doveism .
1936		Lil Hardin Armstrong ‘It’s Murder’ 🎵 ’Cause when my baby makes love to me, it’s murder! / Now, when he turtle-doves me, that’s murder!
1942		‘Digg Mee’ ‘Observation Post’ in N.Y. Age 10 Jan. 9/6: Weldon Clark [...] turtle-doving to Anita Wilson at the Guardsmen’s.
1957		D. Burley N.Y. Amsterdam News 18 May 13: That jive about loving and the turtle-doving.
2001		M. Coles Bible in Cockney 23: What you ’ave just done really proves ’ow much you turtle God.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 194/2: turtledove adj. in love.
2002		M. Coles More Bible in Cockney 21: Hosea still turtle-doved ’er.