What worked for me is ask them to help you get familiar with their energies faster. The faster your energy body can acclimatize to their vibrational frequency (or at least close to) then the more likely you will be able to perceive them in your dreams.
You see our primal brain, once it encounters a being that is unknown or unfamiliar to us, it immediately triggers the fight or flight response. Thus the benevolent ETs respect the distancing and only approach when it is safe to do so for you.