The kind of silly, uncontrollable, constant-movement-causing reaction to love. May result in tackles, tickles, crazed giggling, ":3/X3", lolspeak, mushy talk, and all-around madcap behavior. When constantly repeated, slurs into "blub, blub" giving the impression that the speaker is drowning in love.
Boy 1: Whoa! Did you see his girlfriend just tackle him Is she psychotic?
Boy 2: Don't worry about it, she's just in lublub.