Green’s Dictionary of Slang

daddle v.

[daddle n.]

to enjoy lesbian sex; the implication is of mutual masturbation.

[US]B. Rodgers Queens’ Vernacular 59: daddle (les sl, ?fr sl diddle = to fuck; cf diddle-daddle, killing time, with sl fucking off) to practice tribadism ([...] bumping in a face-to-face position, both vaginas touching).