How to dance in a cape???

Can it tie in front? It shouldn't restrict your movement.

Dancing casually, romantically with FI, you may hold body to body, with your arms around his neck. But for polite social dancing, as in a wedding first dance , though there are several arm positions, you never reach your arms around his neck. Your arms go to the sides, elbows lower than your shoulders. Your left hand goes on his upper arm or at shoulder, and your right hand holds his hand.
Since your arms are never higher than pictured here, a buttoned or loosely tied cape will spread but not come off. Also, check your cape. Those meant to just keep the weather out, fasten with the front parts overlapped. 🙂But a dress cape or theatrical cape has 1 or 2 disguised or clear buttons, so when b
very loosely tied at the neck, the lapel on either side is folded back and buttoned open. Then your cape stays over your shoulders, but the front of your dress shows, and your arms will reach out the front if you hold to dance, and your cape whirls a bit.

If you have not seen this, and your cape does not have the lapel buttons and loops or buttonholes, they are easy. And your seamstress will either use clear buttons, or ones covered to match your cape. Once the lapels are spread open and buttons are fastened, the open front is much easier to move in, and not overheat, than a closed cape.

Is there anyway you can practice with the cape on so you see how it’ll look/work?

I'd definitely do some dance practice in your dress and cape like Michelle recommended!!

See if your arms' range of movement is limited at all, and if there are any dancing (or hand placement) adjustments you need to make!