According to Historic England the phallus is a Roman symbol for 'good luck', so you can tell your mate that next time you draw one on his face when he falls asleep at a house party.
It wasn't all willies, though, the team also found a number of other important carvings, including an inscription which read: 'APRO ET MAXIMO CONSVLIBVS OFICINA MERCATI', in reference to the consulate of Aper and Maximus and a Roman bust.
The inscriptions help to give historians an insight into the lives of Roman soldiers, who it turns out were pretty similar to a lot of men today.
To find such detail is rare, with just 'a handful of such sites in the whole of England', according to Historic England.
Mike Collins, who works as the Hadrian's Wall ancient monuments inspector for Historic England said in a statement: "These inscriptions at Gelt Forest are probably the most important on the Hadrian's Wall frontier.