An Australian man who helped a backyard tattooist ink a large male genital on another man's back has been sent to jail.

Christopher William Lord, 23, was sentenced to 12 months imprisonment with a parole release date of March 12 at the Ipswich District Court in Queensland on Friday after pleading guilty to assault occasioning bodily harm.

Lord was charged with assisting friend Matthew Francis Brady, 24, in tattooing a 40cm long penis onto another man's back after the trio had spent an afternoon drinking at Brady's Ebbw Vale home in October 2010.

Brady was sentenced for his part in the crime in 2011.

The Queensland Times reports the pair had convinced the third man, who is on a disability pension, to get a tattoo of a dragon and tiger on his back.

After he agreed they then drew the penis, testicles and an obscene phrase on his back without the man's knowledge, the report says.

The victim has reportedly since had the tattoo covered after an Ipswich tattooist donated his services.