Trying to keep a straight face as you're slowly tickled, the tickler acting non-chalant like they're just scratching an itch or cuddling up to you, when you both know what they're doing to you.
Feeling your lee wriggle against you with every stroke, letting you hold them even closer, and seeing their barely held in laughter on their giddy face as it gets harder and harder to fight... but not doing a single thing to stop you.
That moment when the lee can't hold out any longer and starts to laugh... and feeling them try to wiggle away from the tickly fingers and closer to your kissing lips at the same time.