You could use the touch begins / touch ends rules for this. You could write:
When a touch begins on this ->
Modify behavior property rotation speed to 1
When a touch ends on this ->
Modify behavior property rotation speed to 0
You can wrap the 'Modify behavior property' parts in Tell if you want to change a different actor, so you could put these rules on a button and have the button tell the blade what to do, like this:
When a touch begins on this ->
Tell actors that have the tag #blade ->
(Modify behavior property rotation, etc)
The dispenser is simpler. Once you've drawn a Nozzle actor you could write a rule like this:
While this is pressed ->
Create new actor 'Milk' at x: 0, y: 0
You can change x and y to move around where the milk spawns.