The 2.1" diameter might give you some trouble getting it into your sigmoid. Unless you are already experienced in depth, you might want to consider something that has a smaller head that allows you to slowly slide it in more easily before it gets larger in diameter. You might consider something more like this:
CT-152French 2 Inch Diameter Silicone Serpentine Colon Tube from Silicone Nozzles
Starts at 3/4" diameter which then expands to the first rib at 1.4" followed by a valley at 1.2". Next rib is also 1.4" followed by a 1.45" rib followed by a 1.5" rib. It then tapers down to a 2" length shaft that starts out at 1.35" diameter and tapers up to 1.45" prior to the next rib at 1.7" followed by a 1.8" rib and then the final rib at 1.9" before tapering up to the 2" diameter of the main shaft of the tube. I went with the
CT-152French 2 Inch Diameter Silicone Serpentine Colon Tube
Price Each: $130.00
Length:28 Inches +$20.00
Color:Black +$2.00
Softness:00-50 Plus Soft
Retaining Ball Size:2.25" Ball
Bore Size:No Open Bore (Solid Plug Style)
Connector 3 Pack:No Connector Pack
Tip Style:Tip B (smooth, tapered)
This will allow you to slowly get more girth as you insert the colon nozzle deeper into your colon. And the material will allow more flexibility than the PVC snake you were looking at. I have been doing depth play for years now and still have only been able to get a 1.5" snake into my sigmoid. Every 1/4" increase in diameter makes a BIG difference in insertion so you might keep that in mind.