Bernard tells this to Lenina after having sex with her. While she is pleased, thinking that he is feeling better, he is dissatisfied with the way things happened. He thinks that giving in to all impulses (such as sexual activity) is a childish reaction, and it makes him feel infantile. He wishes they had waited, and in this way, he would have been able to control his feelings and understand what passion was. He wished he could be an adult all the time. Lenina is confused and does not understand his feelings.
