You are describing what is usually referred to as dream incubation. You do not need to be lucid in order to do this.

I ask a question almost every night before going to sleep, and sometimes I will be able to recognize the signs of my "dream mind" answering the question.

If you just want to have a person appear in your dream, tell your dream mind just that. Think that thought to yourself throughout the day, and concentrate on them at night. Make up a fantasy, that does not need to be sexual, but keep the scene going in your head for as long as you seem fit. Give an example of a dream you would like to have with this person. Show your dream mind what you want. Also, I think it is most important to emphasize how a person makes you feel in the fantasy, what you think of this person, what the person reminds you of.

I have had success doing that and with two weeks of thinking of the same person, she ended up in five or six dreams.