Usually one cool motha-fucka. He is usually a dark eyed, dark haired, tanned skinned, muscular man. They are usually really sweet and chill guys but, they can kick ass when its needed and they hardly lose. A Bertis can drive the sexiest girls wild, and shows them a good time. He is very flirtatious but once in a relationship, that girl is the only one for him. If you get one, keep em.
bertisexual is when you are attracted to somebody who is defined as berti but his real name is not berti. infact we are all in love with berti even berti himself, therefore we are all bertisexual