Some bunnies are naturally more territorial than others, regardless of being spayed/neutered – it sounds like Lola may be one of them. I have a similar problem with my parents’ bunny (who is neutered)… I have to be very careful around him since I smell like my own bunny, so he sees me as a intruder in his territory. If the aggression is a problem, it sounds like you found a good solution with the shower. However, I would advise against introducing the bunnies unless you have an intent to bond them. Unlike dogs, which do well playing together with new friends, bunnies can be very wary of strangers and usually ignore them at best. Especially since Lola is already familiar with your friend’s bunny’s smell, and reacts aggressively, I wouldn’t put them together.

This is something that may never go away. It doesn’t matter how long a bunny has been spay/neutered, a strange bunny smell is going to send them into a tizzy in most cases.

You’ve got a few options: either have your friend change into fresh clothes before visiting (which could seem kind of demanding :o/), or put Lola in her pen, or hang out with your friend in a different area so she doesn’t get mauled.

And like Peppy said, introducing the bunnies is a very, very bad idea. Rabbits don’t have casual playdates. They are very territorial (obviously) and should only be brought together with the intention of permanent bonding.