Here, Bunya is demonstrating his affection for Lucy by grooming her. The head, face and ears are very popular among the buns.
Another way they show their love is just laying together. There's a reason for the term "snuggle bunnies". In the picture below, however, Bunya is trying to get Ethel to groom him (as he did for Lucy in the video).
Not everyone can afford more than one bunny as a pet. In this case, you have to realize that your bun will bond with you - this includes lots of "free time" (out of any pen), snuggling and you rubbing their head and ears (the bun is alpha). Of course, this must be on the bunny's terms. A rescued bun, especially, may have a bad back-story involving neglect or abuse. You have to build trust and comfort with your bun so the two of you can bond. You also have to figure out where your bunny likes and will allow grooming. Discovering your bunny's personality is part of the fun adventure.