What is the class called where you learn new sex techniques or positions?  

Not sure. On the internet, there are postings for tantra and tantric sex techniques. Without further studying the classes, it is difficult to tell whether the sex technique classes are helpful, harmful, or at all useful to a normal person without sexuality problems. The human body hasn't changed that much in the last 1, 000 or 10, 000 years, so natural techniques today are unlikely to be new ones.