Restriégame comes from the verb restregar, which means to rub or scrub. It's an interesting and somewhat intense word that isn't commonly found in everyday romantic songs.
In this song, the singer uses it in a metaphorical and playful way, saying "Y restriégame todo lo que traigas en la mente" (And rub everything you have on your mind on me). He's inviting his partner to share all her thoughts and feelings, no matter how messy, creating a vivid image of intimate communication.
This song is a flirty, confident invitation to stop holding back. Joss Favela tells someone who is staying quiet that unspoken feelings still weigh on you, even when you never say them out loud, so she should just say what is on her mind.
He asks her to be completely honest, and promises to let his own guard down too. The middle of the song turns playful and a little possessive: he claims no one loves quite like he does, and that the mark he leaves behind, "agüita y jabón" (a little water and soap), will not be enough to wash away.
By the end he is reminding her that time to decide is running short, and that he is not going to waste time looking back. At its core it is a song about desire, honesty between partners, and the confidence to ask for exactly what you want.