What would happen to a weak base dissociation equilibrium if more products we added

The position of equilibrium will shift to the left.

Step-by-step explanation:

The general equation for the dissociation of a weak base is

B + H₂O   ⇌   BH⁺ + OH⁻

According to Le Châtelier's Principle, when a stress is applied to a system at equilibrium, the system will respond in a way that tends to relieve the stress.

If you apply a stress by adding more BH⁺ or OH⁻,  the system will respond by moving in a direction that gets rid of the added ions.

The position of equilibrium will shift to the left, forming more of the undissociated base.