Comment by novi on From Points Of Three - Chapter 20

@novi Rope play (or also known as Shibari) technically doesn't require clothes to be removed for most trust scenarios. But when you're intending it for sexual use, it's better to practice on bare skin so you can make sure your knots won't pinch or pull painfully on bare skin, whereas if you tried to practice with clothes on, the layering of the fabric creates different areas of padding or added friction. Which can lead to errors if you go straight to trying the same thing on an undressed partner. 

Sincerely, The Summarizer.