A footjob is not considered infidelity
She already knows everything she needed to know because her parents constantly insisted that she learn all those things. They made her read the Bible and how she had to respect her sister and any man she wanted to get. However, she is a specialist in looking for loopholes in the laws. Because right now he is giving a footjob and he clearly knows that this is not considered infidelity. That’s why calmly while playing the console, he has his brother-in-law’s cock in a good position and he won’t stop moving his fingers until he makes him cum.