A woman's lawyer says she was grossly intoxicated when she performed a sexual act on a man in front of staff while waiting for food at a fast-food drive-thru in Gore last year. 

In the Gore District Court this morning, Judge Russell Walker said it must have been disgusting and shocking for the McDonald's drive-thru worker to witness. 

Counsel Scott Williamson said his client Mary-Ann Ainge (44) could not remember the act which she did on the 71-year-old driver of the vehicle as she was grossly intoxicated at the time. 

The summary of facts, which were not read out in court, said the act happened about 7.49pm on October 27. 

After they had ordered food, Ainge, who was a passenger in the car, performed the sexual act. 

''The act was performed in clear view of the victim who served the food,'' the summary said. 

After the judge said how the act must have impacted on the worker, he said he did not need to say much more. 

"I think you know from your reactions in court today, there are no explanations for this other than you were grossly intoxicated." 

She was sentenced to 12 months' supervision and ordered to pay $250 in emotional harm to the victim. 

- by Karen Pasco, Open Justice