Pegué comes from the verb pegar, which literally means "to stick" or "to hit". However, in the context of dancing and music, the reflexive form pegarse takes on a new meaning: to get very close to someone on the dance floor.
In the song, the narrator sings, "Me le pegué, me pegué, me pegué" (I got close to her, I got close to her, I got close to her) when he sees his ex dancing alone. This action, repeated for emphasis, is the turning point of the song, revealing that he hasn't moved on at all.
American producer Marshmello teams up with Colombian singer Manuel Turizo for a fast-paced dance track about the classic lie we tell our friends after a breakup: claiming we are totally over an ex. The track opens on a miserable note, with Turizo admitting he spends his days drinking and staring at old photos with red, crying eyes. He drops the brilliant line, "No es lo mismo estar solo que estar solo enamorado" ("It's not the same being alone as being alone and in love"). When he is sober, he admits he lied about moving on, confessing, "Borracho dije que ya te olvidé / Pero no te había olvidado" ("Drunk, I said I forgot you / But I hadn't forgotten you").
The mood flips the second he walks into the club. He spots his ex dancing alone ("bailando sola"), moves right up close to her ("me le pegué"), and completely loses track of time dancing together. In the spoken lines near the end, he says, "Esta noche me sacan aquí borracho y contigo" ("Tonight they'll carry me out of here drunk and with you"), raising a glass to her before yelling "Salud!" ("Cheers!"). It is a fun, brutally honest track about letting liquor talk and realizing you want your old flame back.