You just gotta get physical

can go different ways - you can respond just as sexually or you can play it cool and get her to do some dance moves with you.
If nothing is coming to you, I strongly advise taking up some dancing classes. Either hip hop (single dancing) or Modern Jive (partner dancing), I do both. You don't have to go to many classes, you just need to rehearse a few moves over and over

It helps to have both. You sweep a girl off her feet with the partner dancing in key moments, and you just have fun and build attraction with the hip hop for the majority of the time.
But next time just do whatever comes to you. You can only learn. Once you know like 5 physical things you could do, you can just do it with confidence without even thinking about it.
BIG TIP - I see so many guys who've taken partner dancing classes, and they don't have the balls to actually have a decent dance with a girl. Most guys are so afraid of initiating the contact and getting the dance going, that they keep doing this "on and off" thing where they do a few moves, she half heartedly does them with him cause she's shy, the guy immediately thinks she wants to stop so he stops and does this embarassed laugh, or says something with a smile, but the girl doesn't leave, so they start again, and she's still a bit limp wristed, so they stop again, etc. etc. till finally she politely declines him. She's just shy, she's giving the chance for you to sweep her off her feet, that's all you need. If she's limp wristed, give her encouragement, I always say things like "Wow you're really picking this up!" or they stuff up and I laugh and hug them and keep going right into the next move, things like that. Her being shy is PERFECT - she's being the clueless girl while this awesome man comes in and sweeps her off her feet, shows her how its done. She loves to feel bemused.