Why do this? It's not clear how Peat felt about tadalafil but he did say he doesn't like increased NO (which is not the case here). Quote from his November 2015 newsletter:

The nitrate (converted to nitric oxide) was
known to act by increasing the formation of the
"second messenger," cyclicGMP (Kukovetz and
Holzmann, 1983) by activating the enzyme guany-
lyl cyclase, the same enzyme that is activated by
testosterone (and also by progesterone, pregne-
nolone, and DHEA) (Vesely, 1979).
Nitroglycerin's effects on the heart were only
momentary, with serious side effects, and Pfizer
was looking for a better vasodilator, which
directly increased the cyclicGMP. They originally
thought of sildenaftl, Viagra, as a drug for heart
patients, but it turned out to work better for
producing prolonged erections. Though it worked
by preventing the breakdown of cGMP, it was
generally considered to be a substance that
increased the effect of nitric oxide.
The extreme commercial success of Viagra
caused a shift of attention from the toxic effects
of nitric oxide, to its role in virility and relaxing
blood vessels. Even though Viagra acts on cGMP
which is also increased by testosterone, the
culture that developed after the mid-1990s began
treating nitric oxide the way the drug industry had
earlier taught researchers to treat estrogen--if
something good happens in the body, it must be
caused by NO, and if NO has an effect in the
body, that effect must be good.

Note how he never actually says cGMP isn't a bad thing, but rather NO.

Day 0: Tried 4 drops an hour ago, not feeling much yet.