The song in question is Прятки by HammAli And Navai, that phrase is shortly after 1:50.
There are two points to be noted:
• most probably there is no word c there;
• дозу is the direct object of дай.
Although some sites (including YouTube in the link above) maintain there is c in с тобой, I cannot hear it neither there, nor in this live performance, and there is a site which has the lyrics without c.
With punctuation normalized, the phrase looks like this:
Я заторчал тобой. Всего лишь дозу!
Дай себя, пока совсем не стало поздно!
Заторчать is drug addicts’ slang for ‘to get high’ and the c does make difference: я заторчал с тобой is ‘you and I got high’, while я заторчал тобой is ‘I got high on you’ meaning “you're my drug I got high on”. Quite metaphoric, and the metaphor continues in the next words: Всего лишь дозу! // Дай себя, пока совсем не стало поздно! — ‘[Give me] just a dose! Give me yourself until it's too late!’ — meaning “I need you like an addict needs a dose, give me a piece of yourself or I'll suffer from withdrawal.” In fact, Дай себя explains what was meant by Всего лишь дозу!
Всего лишь дозу! — the Accusative case without a preposition can mean only one thing: the noun is the direct object. A sentence consisting of a noun phrase in Accusative without a verb is a typical way to demand a thing, the implicit verb being the imperative дай(те) [мне]! ‘give me!’: There is a famous quote from Richard III by William Shakespeare: Коня! Полцарства за коня! ‘[Give me] "A horse, a horse! My kingdom for a horse!"’ — Коня! is in the Accusative case.
The whole phrase can be translated as ‘I got addicted to you. A mere dose! Give me yourself until it's too late!’