It's good to take heed of signs from people.
Brad and Amy are about to have sex, but Amy seems uncomfortable.
Brad wants to decide whether to keep having sex.
Brad asks Amy if she wants to have sex and stops when she says no.
Brad continues to have sex with Amy even though Amy doesn't seem to enjoy it.
Amy trusts Brad more and doesn't have to feel nervous anymore.
Amy loses trust in Brad and isn't interested in him anymore.