Sure, a bath towel will do the trick, but there’s just something nicer about wearing a robe. (It’s a better ... recommendations that come in a wide range of sizes overall.
If you’re planning on getting changed inside the coat, wide sleeves and a spacious fit make doing so easier. If you’re simply looking to wear a dry robe as a big, convenient layer, details ...
Make the sleeves extra wide, then split each sleeve up the side after sewing your robe together. The black jacket that Snape wears under his robes has a high collar and reaches down to just past ...