A characteristic or an act unique to a straight person. Examples:-
1. Punching a friends hard on the arm, just for fun
2. Brawling in the street after a night out
3. Getting angry because 'your team' didn't win at sportsball.
1: Why are those straight guys arguing over a sphere?
2: No idea, must be a straightism...
When a person is only interested in their own story or topic. Any other topics or speakers are ignored and often talked over.
Bastard: My opinion is that topic 1 is really good and I think we should do it
Fred: Topic 2 is also possible because...
Bastard Having a Converselfie: and I think topic 1 is great because it is my idea
Jane: It could also...
Bastard Having a Converselfie: the other day I saw a duck.