By Declan HarveyNewsbeat reporter
Those who utilize "hook-up" apps to meet up for casual intercourse need to ensure their partner is over the chronilogical age of permission, the National Crime Agency is warning.
It follows a rise that is reported how many teens phoning the NSPCC's helpline with bad experiences after getting apps like Grindr.
One guy contacted by Newsbeat stated he previously been "groomed" with a 24-year-old after going online aged 13.
App developers state users must verify they truly are of appropriate age - over 17.
You can find several free "hook-up" apps which reveal the pages of nearby users - including their photographs and frequently their intimate choices.
These change from old-fashioned online dating services as they are "geosocial" - they could identify users to in just a metre, in place of basic areas like towns - meaning they will have gain popularity with individuals trying to find casual intercourse.
The manufacturer of two leading services, Grindr, that is designed for homosexual males, and Blendr, targeted at straight people, claims around 201 million grownups utilize its solutions. Other people consist of Scruff, Jack'd and Bender.
Aaron, now 18, claims he downloaded Grindr as he had been 13, lying about their age as he registered. He stated he had been simply shopping for individuals to communicate with about their situation.