slut, n. (OED)

2. …

b. In playful use, or without serious imputation of bad qualities.

1664    S. Pepys Diary 21 Feb. (1971) V. 55   Our little girl Susan is a most admirable slut and pleases us mightily.

1678    J. Bunyan Pilgrim’s Progress 112   As the Mother cries out against her Child in her lap, when she calleth it Slut and naughty Girl, and then falls to hugging and kissing it.

1710–1    Swift Lett. (1767) III. 79   Ah! you’re a wheedling slut, you be so.

1741    S. Richardson Pamela III. xxx. 207   Well did the dear Slut describe the Passion I struggled with.

1824    W. S. Landor Imaginary Conversat. II. xv. 278   [Henry VIII] Nanny, thou art a sweet slut.

1884    C. G. Gordon Jrnls. Kartoum (1885) 115   Why the black sluts would stone me if they thought I meditated such action.

transf.

1862    Thackeray Philip xiii,   You see I gave my cousin this dog,‥and the little slut remembers me.