After Gai went HAM on Madara in 8th gate many people specifically Madara fans are saying Madara is simply toying with Gai and is not serious, but I will disprove that.
1. Madara is letting Gai hit him
This is one where people think that Madara is simply taking the hits and not attempting to escape hits since he is a maschoist and enjoys pain. This is false, Madara does not like pain but the rush and feel of battle.
Madara has expressed concern if Gai hit him 4-5 times and cautioned himself to not let himself get hit directly.
You must be registered for see images
Showing Madara is serious and knows Gai is a legit threat to him. Later in the fight Gai goes in for the final hit of the Evening Elephant and Madara immediatly protects himself and attempts to kill Gai by throwing the balls.
You must be registered for see images
Plus Madara always has a look of concern when Gai hits with the Evening Elephant, this is not a look for someone who is enjoying the pain.
2. Madara is not using any jutsu against Gai so the battle lasts.
Onmyoton is the most defensive and can destroy any ninjutsu making it the ultimate defense and offense it is better than anything else in his arsenal against Gai. EMS techinques are useless. Susano would get shot through like a bullet, Meteors take time to prepare(Susano handseals), and Gai can go for him if he tries it, Gai is too fast for genjutsu. Rinnegan techniques are too fodder as well. Deva Path gets pushed back by Gai's pure force(like with 6 tailed Naruto), Ashura Path gets destroyed by Gai's technique, Preta Path can't absorb a thing, Ghost Path needs direct contact which gives Gai a chance to attack. Mokuton gets fodderized by Gai's techniques.
3. Madara being psyched up about fighting Gai and laughing means he isn't trying.
Madara being happy/rushed up from Gai doesn't mean he is toying it means he is happy there is someone strong that he can take on seriously in epic battle. Madara was rushed up in his fight against Hashirama does that mean he was toying with him the whole time no. It means Madara is happy there are strong opponents that can give him a rush. If Madara is just toying then he is not getting the rush, he was toying with the 5 kage and he didn't even get a rush from them like with Hashirama.
In conclusion Gai was actually giving Madara a hard time, as shown by Madara's concern not to get hit, Madra statement about Gai almost killing him, and Madara's rush he feels when fighting someone strong that can hurt him. And btw if Gai hit Madara in the head with Night Gai/Moth Madara would be dead U_U