I feel that most STPs take practice. But some things are right out of the box. So a week or two is reasonable, esp. it seems like you are getting better at it.
Practice to me goes like this: shower, no clothes (or at least no pants); toilet no pants; toilet underwear; around the house; single stalls; men's room stall; urinal; etc.

The only one I graduated from around the house was the Sneekee (I might have with pstyle, never figured how the heck to carry it.) I used the urinal once with it and was so excited I wet myself. LOL
Drinking tea is helpful as a shy stream is not helpful. But you don't want to really really need to go unless this is your usual state. If it is, you need to go more often.

--Jay