One example could be in 'Lolita' by Vladimir Nabokov, although it's a complex and controversial story where an older man is attracted to a young girl. In general, such stories are often disturbing and not to be glorified. Literature sometimes uses these themes to explore the darker aspects of human nature.
No. In any educational setting, there should be clear boundaries between students and teachers. A situation where a young girl tries to seduce a teacher violates these boundaries and goes against professional ethics. It also sets a bad example in terms of appropriate behavior.
No. It is completely unethical. Incestuous behavior, even in a fictional story, goes against basic moral and ethical norms. It can be extremely disturbing and harmful to promote or even imply such behavior.
Definitely not. In most societies, the law protects minors from being involved in sexual relationships with adults. Teens lack the maturity and life experience to make proper decisions regarding sexual matters. And older adults have a responsibility to act in a proper and legal way, not taking advantage of the vulnerability of teens.
It is completely unethical. A young teen is not fully developed mentally and emotionally to make such adult decisions. In society, we have laws and moral boundaries to protect the vulnerable, especially minors from being exploited in any form of sexual situations.
Ethically speaking, this is unacceptable. A young couple may be at a stage where they are still exploring relationships and themselves. An older man trying to seduce them can disrupt their growth, cause internal conflicts within the couple, and is a form of inappropriate behavior that undermines the values of healthy relationship building.
It is completely unethical. A teen is not fully matured mentally and physically, and any form of sexual relationship with an older person in such a context involves power imbalance and potential harm. Society has laws and moral norms to protect minors from such inappropriate situations.