Drake sings this when talking about his phone ringing. "When that hotline bling" just means "When that phone rings" in a
black-culture way. He sings about how he knows when his phone rings late at night and the caller is the particular female character from the song, that it can only mean it's a booty call.
Contrary to the other ultra-white
definition on here, "Hotline bling" is NOT just some term for "booty call", not even close. It's only relevant in this
one song.
Dude 1: Damn
man your hotline hasn't stopped blingin since we left!
Dude 2: Yeah dude it's the bossman, he keeps asking me to work this weekend. Only he can make
dat hotline
bling like that... I ain't takin no calls!