ok.
you apply rudder and the aeroplane rolls. this is because during the yaw one wing is moving faster than the other until the yaw ceases. there after the aircraft will be at an angle to the direction of flight and both wings will be flying at the same speed.
the slipstream rotates around and hits the fin....
no it doesn't.
in reality the slipstream moves straight back past the aeroplane which is why fairings are aligned straight back and work.
of the rear edge of the propeller is a vortex sheet that curls at the prop tips. it is this vortex sheet off the prop that spirals around the fuselage and hits the tail. if you put a little piece of tape on the fuselage, in flight it will stream straight aft for most of the time but as the vortex sheet from the prop passes it will flick around in line with the vortex sheet. on a normal 2 bladed prop you will see 2 flicks per revolution of the prop.
where this impinges on the fuselage depends on the relative speed of the aircraft, the rpm of the prop and the fuselage length.
keep at the theory. it is what makes mastering it all possible.