Double pole plant is an awesome drill to get forward, among others: simply tap both poles, but use that as a cue to recentering and getting back forward. It also helps with counterbalancing (angulation): it's harder to plant both poles if you're leaning too much to one side.
This is actually a very useful cue that you can train into your skiing to help you deal with Survival Reactions: whenever find yourself in trouble and back on the skis, reset and recenter back forward with a forward double pole plant. Kind of a "snap out of it". Your brain will engrain it that way and you'll have a powerful ally when the going gets tough.
Start a green or blue carved run. At the beginning of every turn, swing both poles forward and tap them.
As you swing the poles forward, move the hips forward as well and recenter.
Avoid moving the hands - just swing the poles from the wrists and keep the hands and shoulders largely in the same position.
Other things this drill helps with is counteraction and counterbalancing: because your cue is tapping both poles, trying to reach the snow with both, you'll have to have the shoulders more level and because you're swinging both poles forward, the hands will be more or less held from dropping back.
Here's a very good intro to this drill from Mikaela:
Some sessions working on the same skills:
Another interesting drill is Clapping Fore And Aft++.