What can "To put one's pants into full throttle" mean?
Maybe making the biggest effort to get something?
If you do something at "full throttle", then you are doing it with as much energy/effort as you possibly can.
I've never heard "put one's pants into full throttle". It sounds like something that someone might possibly have made up to fit a very specific context. However, if you actually heard someone say that, I imagine they mainly wanted to convey the idea of putting maximum effort into doing something.