In my experience, simply tightening it enough (ca. 40 Nxm) is sufficient to keep it in place. Locktight isn't necessary, and might even make it too hard to remove in the future. Mine stayed put between 1989 and 2017, and I actually had to take it to my bike shop to have it removed. It had not loosened at all. If you put anything on the threads, a very thin coating of thread anti-seize (like what Park Tool makes -the grey stuff) is all that is required.

(I resisted the temptation to reply in the way you have to me in the past. It would be a matter for gratitude if it were at some point reciprocated.)