Parents have been urged to take more of an interest in their children's online activities after a new study has found paedophiles can groom children in as little as 20 minutes.
Researchers at Swansea University looked at the language groomers use in chatrooms and on social media - and said the results were worrying.
Academics found that paedophiles do not always pose as children and use "highly skilled" techniques to persuade rather than coerce children into doing what they want at alarming speed.
Professor Nuria Lorenzo-Dus and Dr Cristina Izura lead the Online Grooming Communication (OGC) Project - which will be presented at the British Science Festival on Thursday.
Professor Lorenzo-Dus said: "We have carried out a detailed analysis of the language used by more than 100 online groomers which shows that they are skilled communicators who use a range of strategies.
"These include seemingly innocuous 'small talk' to develop a sense of trust in them, requests and commands to gauge the children's disposition to meet online groomers' desires for verbal or visual sexual engagement and compliments on various topics to increase feelings of trust and emotional bonding."
The four-year study looked at chats between 192 online sexual predators and researchers posing as children before analysing the language used in the chat.
It found that the age range of those doing the grooming were between 21 and 65 and the vast majority admitted they were adults - conflicting popular belief that internet paedophiles always pretend to be children.
And academics say they were shocked after discovering that grooming does not take long - with the time between initial online contact and first sexual requests ranging from between 18 minutes and 82 hours.
Dr Izura said: "Online groomers are communicatively, highly skilled and can interact with their victims as if they care about them, and can pretend to be romantically - rather than only sexually - interested in them.
"They complement children regularly on a range of topics, rather than only on sexually-oriented ones.
"We have found that depending on online grooming speed, sexually-oriented compliments, whether on appearance or on personality, comprise between over half and a quarter of all the compliments online groomers pay.
"Moreover, online groomers use compliments not only to develop an emotional bond with the children, but also strategically to frame communicative exchanges in which they desensitise the children to sexual behaviour."
Researchers say the level of online groomers' "communicative sophistication" means that many interactions go undetected by existing online grooming protection software.
They are now calling on parents to get their children to open up about their digital lives and talk to them, frankly and regularly, about how they spend their time online - such as their favourite internet activities, apps or blogs and online friends.
Professor Lorenzo-Dus added: "It is unrealistic to stop children using the internet and it is not always possible to monitor all their digital activities.
"However, increasing their understanding of how online grooming works and the communicative tactics online groomers use will make it possible to recognise the potential dangers."
Dr Izura added: "Parents could try to open up discussions with their children about the dangers on the internet, including online grooming.
"Listening to them carefully and taking an interest in their online activities is a good way to build their trust in us and help reduce the risk of children looking for trust elsewhere online."
The NSPCC in the UK said children are increasingly contacting its ChildLine service about online predators.
A spokeswoman said: "In 2015 a change in the law, as a result of NSPCC campaigning, banned adults from knowingly sending sexual messages to children, as a prelude to carrying out sexual abuse.
"It's quite incredible that a year after this new legislation was passed it has still not been implemented, at a time when police are under crushing pressure to tackle this type of crime.
"We hope these insights into how predatory adults groom children online will help educate young people about staying safe, and assist the police in catching offenders."