Subjectivism (SB) says that moral judgments describe how we feel. To call something "good" is to say that we have a positive feeling toward it.Subjectivism and its problems
The ideal observer view is a further refinement. It says that moral judgments describe how we'd feel if we were fully rational.
These questions are about Chapter 2 of Harry Gensler's Ethics: A Contemporary Introduction (Routledge: 1998 and 2011).
Subjectivism says that our moral judgments describe our personal feelings: "X is good" means "I like X." We are to pick our moral principles by following our feelings.
Subjectivism has problems. It holds, implausibly, that the mere fact that we like something (such as getting drunk and hurting others) would make it good. It gives a weak basis for dealing with practical areas like racism and moral education. And it tells us to follow our feelings but gives us no guide on how to develop rational and wise feelings.