Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Sexual opportunism is the selfish pursuit of sexual opportunities for one's own sake when they arise, often with the negative moral connotation that it, in some way it "takes advantage" of others, or "makes use" of, or "exploits", other persons for sexual purposes. Sexual opportunism is sometimes also defined as the use of sexual favours for selfish purposes unrelated to the sexual activity, in which case taking a sexual opportunity is merely the means to achieve a quite different purpose, for example, to advance one's career or obtain status or money.
This concept is related to quid pro quo sexual harassment, which is defined by Cornell Law School as "sexual harassment in which a boss conveys to an employee that he or she will base an employment decision, e.g. whether to hire, promote, or fire that employee, on the employee's satisfaction of sexual demand. For example, it is quid pro quo sexual harassment for a boss to offer a raise in exchange for sex."
A study of women's fertile-phase sexuality found out that compared to the luteal phase, fertile women may show more interest in sexual opportunism, specifically meaning that they may be willing to engage in and have interest in sex with attractive men, even if they do not know each other well.
See also
Casual sex – Certain types of human sexual activity outside the context of a romantic relationship