Hanairo Virgin Soil

Hanairo Virgin Soil summary:

Our main character, Nagisa, was asked to become the nude model for a product, who's concept is "The Sexual One". In order to get used to his body, Fumitaka Kuga offers to help, including allowing Nagisa to stay at his apartment.... for a price. Now, Nagisa must undergo rigorous sensual training everyday and must stay nude in front of Kuga.