First Example:
Sandra: Have you seen the new Calculus professor, Mr. Crow? He's really handsome.
Patty: Oh my gosh! You have the hots forteacher!
Sandra: I do not! I was just surprised that he's so young, and kinda cute.
Patty: (sarcastically) Sure, I believe you. Did you check if he has a wedding ring?
Sandra: No! I would never date my teacher.
Meaning: The expression "to have the hots for" someone means to be strongly attracted to someone. The idiom is most often used by another person, often in a teasing manner as in the example here. Here, Patty jokes that Sandra "has the hots for" the new professor after Sandra comments on the teacher being handsome. (usage note: when using this idiom to discuss a teacher, no article is used, presumably due to the 1980s Van Halen song "Hot For Teacher")
Second Example:
Kevin: Are you going to Tina's party this weekend?
Jeff: Maybe. Why do you ask?
Kevin: Well, we all know you've had the hots forher since High school.
Jeff: What makes you say that?
Kevin: I just always thought you had a crush on her but didn't do anything because she was dating Michael. Now that they've broken up...