This guy is just curious once he is done feeding his curiousity he will go back to normal,,,,each one of us must have wondered at some point in time what happens behind closed doors,,,,infact his curiousity is a good thing just encourage him to use the same in other factors affecting life... u never know he might become the next gertrude mungai.... and his opening speech would go like.... After years of observing couples or soon to be couples having sex or making love whichever is applicable i have noticed that there is a gap in the act that has proven to be the most important in any marriage........
Its just me
whatever choice you make in life make sure that you can live with it.