The Ministry of Public Health in Thailand is warning teens to purchase right-sized condoms to avoid the spread of sexually transmitted diseases.

The agency said teens are buying bigger condom sizes (which that are too big to fit properly) because they don’t want to be teased by their friends as having a small member.

Ministry spokesman Somchaichote Piyawatchwela said men who use bigger condoms will slip off during intercourse, resulting in unwanted pregnancy and the spread of STDs.

According to the Thai Bureau of Epidemiology, the infection rate of sexually transmitted diseases among teenagers had an increase to 34.5 per 100,000 from 7.53 for every 100,000 people in 2005.

The agency said it expects to spend $1.95 million to give out 43 million free condoms to men and women.

In Bangkok, the Moral Promotion Center has urged teenagers to avoid premarital sex on Valentine’s Day using the “Just a Meal for Valentine” campaign.

The center’s Director General Sin Suesuan said data suggests 83 percent of Thai teenagers plan to have sex on Valentine’s Day, typically in a secluded area after a meal.