My boyfriend was supposed to be watching my back, and alerting if anyone comes. I get behind a roadside ditch, situated by a lay by. I take my panties to the side and start playing with my pussy. Loudly I start to orgasm, but am distracted by the sound of a loud engine coming from behind me. Soon after I realise a highway maintenance lorry driver has been parked right behind me the whole time and the driver was getting a free live show from his wing mirror. The embarrassment is written all over my face. I should have gave the lorry driver an invoice for his naughty voyeuristic ways!