The campaign featured two London Underground posters, one of which carried the headline "He was going so fast he went for the wrong entrance". A second poster read: "Once he'd found the right zone, she was raring to go."
Both executions are part of Red Devil's "Beware his influence" branding drive, which aims to encourage consumers to try out new experiences that might have an element of risk involved.
Complaints about the ads said that the posters referred to anal sex and sex, and were offensive and unsuitable to appear on a poster.
Britvic defended the ads, arguing that although they were suggestive they were open to interpretation and were intended to be playful and cheeky, not overtly sexual.
The Advertising Standards Authority dismissed this and said that some would clearly understand the headlines to be a reference to anal sex and sex, and that they were not suitable for posters.
The watchdog said that the two posters were likely to cause serious and widespread offence and told Britivic not to repeat the approach.
The poster campaign was part of a £4m ad campaign launched by Britvic Soft Drinks as it chases market leader Red Bull. Red Devil also competes against V, Shark and Coca Cola-owned Burn for market share.
Britvic bought Red Devil in 2002 after shelving attempts to launch its own energy drink targeting 16- to 24-year olds.
It is the second time Red Devil has run into trouble. In 2000, it ran a controversial campaign featuring hardman Vinnie Jones. One of the ads showed a bird crashing into a window and was the most complained about ad that year, chalking up 390 complaints from the public.
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