Spermy tit , is when you want to experience the feeling of sucking milk from your girlfriend's tits but she cannot lactate.
Therefore you proceed to ejaculate on her tits aiming for the nipples and then you start sucking your own sperm from her nipples pretending that it is actually milk from her. (The process is not considered gay because your are drinking your own sperm not someone else's |it is however considered gay if you do that with another male)
Last night I was thirsty for milk and I gave my girlfriend the "spermy tit".
Man if you want to feel like a baby try the "spermy tit" it's great.