Both When You Feel like Fapping and When You are Fucking
Four independent stories. The first story takes us to a hot spring. In the Second story alcohol brightens up the mood. In the third story a drummer gets lucky. In the fourth story an A student wants some more hands on practise.
Part 1: A very popular orchestral happens to have a lewd switch, and when that switch is turned on there is no turning off until she's satisfied!
Part 2: A tutor for a wealthy boy ends up turning him into an A student, however he has a proposition for her for some "extracurricular activities" so that she can continue her tutoring...