Does placing a piece of cloth around the waist to prevent late drops of urine from reaching the Ihram garments invalidate the pilgrim's Ihram?

There is no harm for the questioner to tie a piece of cloth around his waist out of necessity, without knotting it, and to tuck it in under his ihram garment, not over it. It is worth noting that the Malikis stipulate that the tying must be under the ihram garment, otherwise a fidyah (expiation) is required. The Hanafi school, however, has a more lenient view.