How this influence will affect your friendship will be up to the two of you, and will depend on various factors: how you each normally deal with strong emotions, since this will intensify them; how well you'll be able to work together, because you could potentially accomplish a lot. Basically, this influence is one of very potent force! But for a lot of friends, it could turn out to be hard to deal with, as it could lead to battles of will, with your pal taking the authoritarian side, allowing themselves to be completely overtaken by the unconscious and overwhelming feelings of power they experience.
This kind of pairing of irrationality and stubbornness is obviously not the best use of the power generated by this influence, nor will it be the most fun. But you could work as a team and divert all that intense energy into a project that you'll work on together. After all, with this influence on your side, together you could move mountains!