Please note that this is the Narutopedia's article on Explosive Tag technique used by Hanzō. If you are looking for the article on technique used by Koharu then you should head to Explosive Tag Extraction Technique.
Placing their hand on the ground, the user releases a large number of explosive tags that stream towards the target, before wrapping themselves around the victim from the feet upwards. Once in place around the target's legs, the tags detonate simultaneously, engulfing them in an enormous explosion.
On one occasion, despite Hanzō commending Nagato for having avoided this technique, the latter still suffered permanent damage to his legs that severely restricted his mobility, attesting to just how destructive the final explosion actually is.
In the anime, Hanzō uses this technique in his battle against the Sannin. In it, he uses a sequence of four hand seals. In Nagato's flashback, he just slams his palm on the ground.