Young adults are to be urged to carry condoms when they are out "on the pull", as part of a government sexual health campaign.
The campaign looks at 'pulling pants' in a new way
It will focus on 18 to 24-year-olds. Just 20% of people in this age group say they carry condoms on a night out.
The £4m campaign warns sexually transmitted infections like chlamydia are rising fast among young people.
Health groups backed the drive, but pointed out that a further £46m had been pledged to the campaign.
Adverts will appear on television and radio, in magazines and online.
The TV ad, which will appear from 20 November, shows couples, with the name of an STI clearly displayed on clothing or jewellery, which aims to show that in real life, such infections are not so easy to spot.
'Sky-high' infection rates
Public health minister Caroline Flint said: "Improving the nation's sexual health is a key government priority and improving access times to sexual health clinics, chlamydia screening and this campaign will all help to drive down the number of cases of STIs.
"Some STIs like chlamydia are on the increase amongst 18 to 24 year-olds and it is vital that we deliver strong messages about using condoms to prevent them.
"The aim of this campaign is to make carrying and using a condom among this age group as familiar as carrying a mobile phone, lipstick or putting on a seat-belt.
"This is not about encouraging promiscuity, but saying to those who are already sexually active: sex without a condom is seriously risky, so always use one."
Nick Partridge, chief executive of Terrence Higgins Trust, said: "Ongoing condom awareness campaigns are a vital part of improving sexual health.
"We must also make sexual health services easier and faster to get in to, then we'll see our sky-high rates of STIs begin to fall."
Deborah Jack, chief executive of the National Aids Trust, welcomed the campaign, but said: "Only £4 million has been committed to this campaign so far, although the government had promised to spend £50 million over three years.
"It is vitally important that the government keep its promise to spend the additional £46 million over the remaining two years.
"Even in a time of budgetary constraint, to cut back on a sexual health campaign is the worst kind of false economy."
However Ann Furedi, chief executive of the British Pregnancy Advisory Service, warned: "Historically, whenever there has been a shift away from hormonal contraception like the pill, towards barrier methods like condoms, rates of unplanned pregnancy have risen as a result."