What are some tips / drills for teaching chasse

I find that some athletes have difficulties getting the timing and stepping down. Are there any drills to help them learn this? What are different ways to explain this dance move to them?

get them to learn it without arms first

i tell them that their back foot is playing "catchup" to the front foot or that the back foot wants to "kiss" the front foot

I begin with them laying on the floor with their feet up in the air (in a pike). I have them put their feet in fifth position and work on the turnout in the hip. I then have them do "beaters" where they are to pull their legs apart (straight) and bring them back together...slow at first and then speed it up. Slow them down if they start to bend their knees....some common mistakes are losing foot position, knees bending or keeping their thighs together and only "beating" their feet. I then have them work on arms positions while laying on their backs. I progress this to standing position where there is no forward movement. Then I progress them to the forward movement. Make sure to cover the topic of plies' and moving feet from fourth to fifth position. I find moving forward to soon prompts leaning the upper torso so I begin very basic. I also use the Megan suggestion of the "chase" and "kiss" as well as Justine's suggestion of no arms and with arms side middle "airplane arms".