I agree with those who said to just being yourself.
It will happen when it happens - maybe he's waiting for just the right moment, I know that I always want a first kiss to be memorable, so while I may want to kiss a person for a while, I won't do it until the time is right, Lord willing. Plus I like to go slow, drag out the beauty of the firsts, enjoy it all step by step. It's sort of like drinking wine, you don't get quite the experience if you chug it compared to going
And flirting? It's all about the non-verbals. A shy smile, a poke or a tap, or even saying something in a flirty way like, "hey boy" instead of "hey roger". Non-verbals say a ton.
When I was on a walk a month ago with a girl I like she just sort of poked my palm (I was ahead of her with my hands behind me). It was flirty and fun and I loved it. In response, I turned, grabbed her sunlit hands, rocked side to side, and spun her, dancing to the swaying flowers and flowing stream. Neither action was expected.
Try asking if he's ticklish, and if he says why, just say "just wondering" with a shy smile. It hints toward more without actually fully risking embarrassment.