Never tried the anal route, but after IV, the biggest rush I’d get from Meth was through oral consumption, so I imagine plugging would give good results. The reason it’s more dangerous is because it’s a higher Bioavailability than other routes, and you plug one dose rather than building over time like with smoking or snorting.
If you haven’t done it before, start low and see how it goes, and then judge your next attempt accordingly.