The child is always at some time guilty of this spirit of exhibitionism. It means this – to much interest in self, too ready to talk about self, too ready to call attention to self. This is very elementary psychology, but it is something of which the child is always guilty, and the business of parents is to check such tendencies in children. The child always likes to be the centre of the circle. It is one of the results of sin and the fall – exhibitionism – self manifesting itself. As we get older we are a little more subtle in the way we do it. The child in his innocence is not conscious of what he is doing; he is not aware of this folly. The child does it openly, but the adult talks about his good deeds, talks about his activities, or tells his experiences, of marvellous and wonderful things that have happened. The application is perfectly obvious. There is a type of Christian, unfortunately (God knows we have all suffered from this, and maybe are still suffering – God have mercy upon us if we are) the kind of person who, the moment he begins to talk, talks about what he has done and seen, and gives you a list of his good deeds – exhibitionism! What a subtle thing it is, and perhaps it is one of the last temptations to leave us, even tempting us to say that we are humble! We can be proud of our humility, indeed I think we always are if we try to give the impression of humility. If our humility is not unconscious it is exhibitionism. So long as we are in the stage of always letting people know what we are doing, and giving an account of ourselves in any shape or form, it is exhibitionism.
– Martyn Lloyd-Jones, Expository Sermons on 2 Peter, p. 248.