You don't even have to play it. From the DailyMail (UK).
Scientists find that carrying a guitar increases your chance of getting a date by a third
by Victoria Woollaston
May 7, 2013
Carrying a guitar can increase the chances of you getting a date by a third, according to a study by researchers from the University of South Brittany.
The study found that women were 31% more likely to give their number to a man carrying a guitar-- double the amount of people who would give their number to the same man when he was empty-handed.
The study was led by Professor Nicolas Gueguen, a researcher in behavioural sciences at the University.
Gueguen hired a 20-year-old man to approach 300 women aged between 18 and 22 in a shopping centre in Brittany. The man told each girl that they were 'really pretty' and asked for her phone number so they could arrange a date.
For the first 100 women he was holding a sports bag. For the next 100 women he approached them holding a guitar case. And for the final 100 women, the man had nothing in his hands.
When the actor was carrying the guitar case, 31% of the women gave them his number. When he was carrying nothing, 14% of the women gave them his number. The biggest turn off for the women was when he was carrying the sports bag, which had a success rate of only 9%.