http://www.glenbrook.k12.il.us/gbss…tors/u3l3c.html and scroll down half way to the president picture and the “Eat at Ed’s” sign examples.
Tension increases as the line approaches 180 degrees, just as Magnum said. However, what he didn’t mention is that your stretching arm has to apply more force to counter that increasing tension. If you want to stretch your dick harder, fine, but it doesn’t matter which way you pull. Whether or not you have a weight draped over your dick, 10 N of pulling force produces 10 N of tension.
The closer the line gets to horizontal, the less “share” the y component has of the tension. Since y supported by the line has to equal the weight of the picture, tension increases until y gets enough to hold the weight (or the line breaks if it isn’t strong enough). As I said though, this isn’t “free tension.” In the sign example, sturdier nails are needed for the smaller angles. Nails that would hold when the line is 60 degrees might break off at 15. When v-stretching your dick, you have to pull harder, increasing tension, to bring your dick closer to horizontal.
That’s my stab at it.
I think Nedd is just pointing out that v-stretches don’t give something for nothing.