The Daytime Tiger, contrary to its appearance, is purely taijutsu in nature and is nothing more than an incredibly fast punch, as Might Guy has noted.
After opening the seventh of the Eight Gates, the user places a palm facing forward in front of their face with one hand and then taps it with his other hand, formed into a fist, which creates a massive amount of air pressure. Next, the user forms a unique hand seal resembling a tiger. This launches the air pressure at the opponent in the shape of one by leaving a gigantic tiger-shaped impression into the initially built-up air pressure with the hand seal. The air pressure will condense as it's moving and be focused into a single point. The technique then explodes on command, releasing the built up air pressure in an instant. A massive explosion — one that dwarfs Island Turtle — is created which can be felt a significant distance away.
The unique hand seal used in this technique resembles the "Tō" (闘) seal, also known as the "seal of the outer lion" which is used in the practice of Kuji-in.
Hirudora may also be written as 昼ドラ, which is a contraction for hirudorama, meaning daytime TV-drama. These were Japanese soap-operas aired during daytime, primarily aimed at female audiences. They all disappeared in the early 2000s, due to cost, DVD, DVR etc. This ties in with why Naruto feels the technique's name is melancholic and old-sounding to be used by Might Guy, who is so obsessed with youth.