= to make love, to flirt.
The expression may, I think, be characterised as a vulgarism; while spoon, as verb, originally student slang, may be considered as slang > colloquial.
stow
»Stow it!» he says. (T. T. T. 161. 14.)
Uneducated individual.
»Oh, stow that», she says. (T. T. T. 141. 15.)
The same.
= hold your tongue!
Cf. Shut it!