I have had solid results with the elliptical tubes from vacu-tech and have found that the shape allows a different pumping process than round. Because (if sized correctly) you have restriction in one dimension, you will be able to focus on expansion in the other dimension. Obviously, this only works if you choose a size that you don’t swim in. In this case, you’ll find little if any difference between an elliptical and regular round. In other words, if you don’t touch the sides, the shape won’t matter.
My suggestion is to choose a size that has a minor axis that is either your present diameter or slightly larger that you can pack to quickly. Once you are anchored in this dimension, you will focus expansion on the major axis diameter of the tube. This is the most basic use of the elliptical tube and it’s pretty cool.
But there are a couple other uses of this design that are creative and fun. The first is a simple 90 degree turn of the cylinder to reorient the minor and major axes. This anchors the alternate diameter and encourages expansion in the other. In most penises (?), the left to right diameter will be greater than the up to down. By turning the cylinder to restrict the dimension that is normally the more expansive, you create compression and expansion in the opposite way you normally "exist". Sounds a little like stress, huh?
Another way I have found to use the tube is to do a 45 degree turn from the "normal" position. This creates expansion potential at 10:00 and 4:00 while anchoring at 2:00 and 8:00 (or vice versa). The effect of this position is entirely different under vacuum and feels different based on which way you normally curve.
And lastly, you can do a dynamic combination of moving through these positions (and every angle in between), rotating the tube. If sized correctly, you will alternately anchor and offer expansion to the whole 360 degrees of your circumference. Make sure you have adequate lubrication if you do this as there will be more dynamic friction than normal pumping.
Again, all of this use is based upon proper sizing so that you can moderately restrict one dimension, while having room to grow in the other.
So how do you size? I have two suggestions:
1) Figure out which round tube diameter you can fit and either pack immediately or with a few minutes of pumping. That diameter is the most you want as the minor axis of your elliptical cylinder. For instance, I can pack a 1.75" cylinder right away, so I would choose that (or one size smaller) as the minor dimension of the cylinder.
or another model for sizing…
2) Figure out that cylinder’s circumference with the classic formula of diameter x 3.14 (pi). For example, a 1.75" diameter cylinder has a circumference of 5.495". To figure out the circumference of an elliptical cylinder use this calculator:
http://grapevin e.abe.msstate.e … llipsetank.html
Enter anything you want for length ( I suggest your BPEL) and the calculator will kick out both the perimeter (elliptical "diameter") and also the volume of such a tube. You can compare this volume capacity to the capacity of a round cylinder at the same length using this calculator:
http://grapevin e.abe.msstate.e … l/cylinder.html
Be sure to divide the diameter in half to get the Ro figure. Enter "0" for the Ri.
One word of advice on the sizing in regards to vacutech. I have found their sizing to run slightly large. They have improved their tolerances since product launch, but I think you are safe in assuming that no cylinder you order should be smaller than advertised. They will likely run a little large (1/8" or so). You don’t want a tube that doesn’t provide the compression/expansion effect (in my opinion). So if anything, size the minor dimension a little lower that you might otherwise and it should work like a charm.
As a sizing example, the best tube I have is marked 1.5" x 2", but is really more like 1.625" x 2.125". This gives me a perfect compression on the minor axis.
If you’ve been pumping for awhile with round cylinders, the elliptical is a pleasant change offering new forces if sized correctly.