On an aluminum frame Smith, synthetic grease. Gun oil does not adhere well to the frame.
I use TW25b and have had no problems. Grease the rails, barrel lugs, bell mouth at the muzzle of the barrel and the barrel hood. Remember that a dab will do ya.
If it is colored grease - white or red - and you can see it on the rails and barrel, you used too much. Wipe the excess off with a Q-tip.
When properly applied you should see a sheen where it was applied. But no streaks or globs. Hope this helps. Regards 18DAI