In a playfully joking way. This is the adverb of waggish, so it describes HOW someone says or does something: with light, teasing humour, usually with a straight face. You most often meet it attached to a verb of speaking or looking — 'he remarked waggishly', 'she waggishly suggested that…', 'he winked waggishly'. Writers use it to tell the reader 'do not take that line seriously; the speaker was being funny'. Like waggish itself, it belongs to books rather than to talk. It is old-fashioned and a bit literary, and it also carries a faint smile from the writer — some writers use it half-mockingly, as if gently laughing at how pleased the joker is with himself. In everyday English you would just say 'jokingly', 'as a joke', or 'teasingly'.

詼諧地、開玩笑地（帶點頑皮）。書面語、偏舊式；口語直接說 jokingly 或「開玩笑地說」。