A man who is sexually active who is also the coherent owner of a small penis (small meat).
Also a woman/male who has a sexual encounter with a man with a small penis can be said to of had a (Small Meat Romance)
Bob; did you see lil Jerry in the shower today after football? Didn’t realise he was a small meat romantic
George; yeah only just tho, poor bloke wasn’t given much in the penis department, can’t believe his wife is so open about her small meat romance