[Tandem mama]

I've been playing around with this and doing some experimentation with my kids. To see what gets a better and quicker reaction. So far today, these our my experiences.

Cuppycake standing on a chair in the library:
Sit down, please. "no"
Sit down, cuppycake. (she sits)

Again, she stands (they shouldn't put the toys so far out of little ones' reach if they are going to get upset every time they climb the table or stand on chairs to reach them, just sayin')
Can you sit down? "no"
Sit on your bottom. (she sits)

again.

Sit down. (sits)

AHA!!! Cuppycake needs two word commands, spoken in a normal tone of voice, not stern (stern can make her cry easily) unless it is dangerous. She cannot understand please to be a command, it seems.

Sunshine getting into her carseat
can you please put your arms in your straps while I buckle sissy? "I want you to do it"
ok i asked she answered.

sunshine getting into her seat properly now that I was able to help.
Sit back right please. she complies
Give me your arm. she complies.
Other arm please. compliance.

it seems Sunshine understands that please is polite, not request.

I will continue to experiment with this with my children, since it seems to be an individual thing whether please denotes request.