My dog had his first erection after bath. Is this normal? Neuter him?

Wrigley is such a handsome boy! Dogs can get erections even if they are fixed or not, I have a three year old fixed Basset Hound who occasionally gets them. Since you had just given him a bath, I would be more likely to attribute his behavior to his excitement from having a bath and having it be over than the erection. I'm not sure how old he is, but male dogs typically do not become fertile until they are six months of age or older. If Wrigley is at least four months old, it's fine to schedule his neutered at any time. Some people like to wait until around a year of age, which is also fine, but just be sure to keep him completely away from any intact females or there may be puppies on the way! Best of luck, I hope this helps!