Obviously tip stalls occur when one wing reaches the critical angle before the other. Ailerons/flaps alter the lift of the wing by increasing or reducing the camber(angle of attack of the wing) and if you have flaps down during a stall the aircraft will have a less nose high attitude than what would be normal in a stall. This is because the wing reaches the criticle angle sooner because with the flaps down, the plane has a higher AOA  to start with. The stall will be slower but it will be more level and sometimes more violent. Ailerons work the same as flaps by increasing the AOA and consequently lift on one side and reducing the AOA on the other side thus decreasing lift.
Pretend that during a state of equilibrium you apply 'left' aileron. The left aileron will go up and the right will go down. This will reduce lift on the left side and increase lift on the right. this will initiate a roll to the left. Now pretend the the aircraft flying straight and level, slow it down so that it is just starting to get 'mushy' on the controls. Now again gradually apply left aileron as the plane slows right down. Eventually the plane will roll to the right.
This is because on the right side the aileron has gone down increasing the AOA and therefore stalling the right wing before the left one causing the plane to tip stall to the right. So even thought you have applied left aileron the plane rolls to the right. In full sized aircraft this has resulted in a destroyed airplane and a dead pilot because it is unexpected and surprising. Or for models a broken pane. This is why it should be stressed to new flyers that during the hold off and other slow phases of flight roll and yaw should be controlled with rudder only. If a tip stall happens during the hold off the plane will be headed for a cartwheel