Anytime, Natsumi uses the laugh pressure point on Tsukasa, causing him to lose his composure.
In Kuuga's world, Tsukasa was a policeman and when Yashiro and the others were having a discusion,he just barge in with a blank face in front of the bosses, pouring hot water in one of the cup until it is overloaded before slowly moving to the other side while still pouring it until the hot water is was used up.
This dialog from the Ryuki World arc. The set-up: Natsumi has been falsely accused of murder, and Tsukasa, despite making jokes about her being a cold-blooded killer, is trying to save her - except that in this world, legal cases are decided with Rider battles.
Zolda: I won't let an amateur make the verdict! She's guilty! Guilty! (fires giant shoulder cannons)
Tsukasa: Who the heck's that?!
Ren: Probably the public prosecutor.
Tsukasa: Suddenly I very much want to prove her innocence.
The whole Den-O episodes counts, starting with the whole getting possessed thing, up to the climax, where Kuuga mistakes Den-O Momotaros for the enemy, kicking him on the neck, down to the bad guy breaking character and telling them to get their acts together, finally culminating in Momotaros' and Kuuga's..."Combination Attack".
Speaking of Den-O, there's the scene in Kabuto's world where Tsukasa puts the Taros' Attack Ride cards to use... and they're all completely worthless as all they actually do is make Tsukasa spoutCatch-Phrases.
Decade:Ore, sanjou!note I'm here
Decade:Then how about this? *changes to Gun Form* Can't hear your answer!
Gatack and ZECT Troops:But you didn't ask us anything...
To add up to the awkward feel of the scene, the Decadriver repeats each Taros' catchphrase in a heavily English-accented Japanese.
During the aforementioned Den-O episode, Tsukasa's actions allow him to change the Den-O Form Ride from the Denliner to Momotaros himself. After transforming the camera angle makes it seem like Momotaros has grown giant Super Sentai style... only for it to cut and show he's just regular size and thought he was giant.
In the World of Hibiki, Kiva-la decides to summon Ouja to release a very large sized Bakegani. Unfortunately for Kiva-la, she proceeds to get hit by Ouja's kanabo right into the TV screen.
Mind you, this Ouja is not the AR Ouja, but the original Ouja (in other words, Asakura himself)...
In episode 28, Amazon is getting his ass kicked...
Tsukasa: "Ah." *Holds up baseball instead of change card, complete with revving sound effect.*
Den-O: *kicks Mook out of the way* Stop interupting me, you bastard! Ore, sanjou! Man I'm the coolest.
The net spinoff videos. All of them. Decade gives henshin pose lessons, Narutaki obsesses over butts, and even the actors themselves have a hard time maintaining character in the face of the crazy goings-on.
Also in Hyper Battle DVD: Protect! The World of Televikun. Tsukasa, Yusuke, and Kaito fight over for the magazine and accidentally dropping Natsumi's cakes. Kaito immediately accused Tsukasa and Yusuke, who dropped the cakes. Natsumi find out that Kaito himself dropped the caked, and directly using her signature Secret Laughing Pressure Point to Kaito. Then she talks to the audience...
Natsumi: "Blaming someone else is the worst thing you can do."
One of the funniest bits of the Decade Net Videos has to be Narutaki reverting from being a jerkass into the little boy who worships Kamen Rider V3.
One of the segments is about Riders' weapons, which causes Narutaki to scoff that the Heisei Riders are wimps for needing weapons, unlike the Showa Riders who mostly just used Good Old Fisticuffs. Then when it turns out that the first Rider to use a weapon was the originalnote Because he stole a sword from a Shocker Mook during one battle, Narutaki praises his cleverness. Tsukasa calls him out on being a hypocrite.