Luffy couldn't help but notice the size of Robin's nipple compared to him. It was only just smaller than him!
It didn't help that Robin was still moving at this point, her nipple constantly pressed Luffy against her bra. Although Robin hadn't noticed the little man in her bra, but her body must have, as her nipple had become erect. This pressed Luffy much harder against her bra. Luffy had eaten the rubber fruit so it didn't hurt but that doesn't mean it wasn't annoying.
Luffy tried to climb out but it was no use. He simply couldn't get out with Robin constantly moving like this. Suddenly, Robin's nipple slid straight into Luffy's mouth and the sweat acted as a lubricant, making her nipple slide in and out with every step. Luffy tried to take it out of his mouth but it was so big that his teeth got stuck. Luffy was forced to taste the sweat that had formed over the day.

After 2 minutes, Robin tried to relieve an itch on her breast which slid her nipple out of Luffy's mouth. Robin continued to scratch causing Luffy to slip out of her bra and fall. Her belly was sweaty from the heat and made Luffy's journey quite slippery. This time Luffy thought he would definately land on the floor. But yet again he was wrong. He slipped through her panties and landed in her bushy area.

His arms and legs got tangled and he couldn't move... but he could still smell. He could smell Robin's fluids and the smell was too strong for him to handle and he almost passed out. Robin felt something in her panties and when Nami wasn't looking she started to scratch violently. Obviously, this didn't work in Luffy's favour. She managed to untangle him from her hairs but the constant scratching caused Luffy slip into her vagina. He was so small Robin didn't even feel him slip in. Luffy had to get out, but the smell was so strong he couldnt concentrate, he began to feel faint and after a few seconds he passed out inside of her.

Robin:'Nami-san we've been looking for 10 minutes and we haven't found him, where could he possibly be?'
Nami: 'Oh he's probably doing something stupid with Usopp and the other guys, let's leave his hat in the kitchen and go back to getting our tan.'
Robin: 'Actually, I'm starting to feel quite tired, I think I'll go take a shower and a nap before dinner.'
Nami: 'Oh thats a shame, I was enjoying spending the day with you. Oh well, see you later Robin!'
Robin: 'Bye!'

Robin went into her room and took off her panties. she was leaning over as she did this which made Luffy slip out. He landed on the floor and Robin didnt see a thing. She entered the bathroom leaving Luffy on the floor. Luffy woke up and realised he was no longer trapped inside Robin. He tried to move but the juices from Robin's body had dried while he was unconscious causing him to stick to the floor. Once again he couldn't move and was in a bit of a sticky situation (no pun intended). Luffy then had an idea.

'Maybe if I use gear third I'll grow enough to get me unstuck!'
'Yosh, here I go! GEAR THIRD!!'

Luffy's hand grew 5x his size which was just enough to get him unstuck. Now he had to think of a way to get his nakamas attention at his size. He decided the best thing to do would be to go to Usopp, his best friend. He didn't want to waste any time so he grabbed two legs of a nearby table and got ready to blast through the door.

'GUM GUM ROCKET!'

Luffy shot through the air and was heading straight for the door. But unfortunately at the same time Robin stepped out of the bathroom and got in Luffy's way. Luffy landed on her leg. He still had some juices on him and was once again stuck.

Robin felt something on her leg and began to scratch it. During this process, Luffy got caught inside her nail just as she was finishing. Luffy didn't know what to do, but he had to think of something fast. Unfortunately he didn't have enough time to think because Robin started to put on her panties. As she did this, Luffy fell out of her nail and into her pants for the second time that day, this time on the backside. Luffy had no time to react because 2 seconds later her was was stuck to one of her butt cheeks.

Luffy heard Robin yawn and remembered that she said she was gonna take a nap. Luffy started to struggle much as possible but it was no use, her pants were on too tight. Robin laid down on her bed and fell asleep almost instantly, leaving Luffy to get crushed on her butt. Luffy was stuck like that for 45 minutes before Robin rolled over to her front. Luffy thought this would work in his favour, but all it did was cause him more trouble. As she rolled over, Luffy started to roll towards the centre. He tried to hold on to her panties but it was already too late. Luffy fell down her crack and landed face first in her asshole. The smell in there was too strong for Luffy and he passed out instantly. Luffy eventually woke up, still inside Robin's asshole, but he was able to handle the smell slightly better. Luffy tried to squirm out, but the sweat caused him to slide further in. Now his whole body was inside Robin...... Again. Luffy was stuck like this for an hour until suddenly Robin let out a massive fart that sent Luffy flying out of her ass and back into her panties. Luffy couldn't take this anymore.

'GEAR SECOND! GUM GUM JET PISTOL!'

Luffy easily managed to punch a hole in Robins panties and climbed out before anything else happened. He ran out from under her skirt and jumped off the bed onto the floor and ran towards the door to get help. He got to the door and prepared to break through it.

'GEAR TH-'

Luffy was cut off as the door flew open showing Nami's silhouette.

'NAM-'

Luffy was unable to talk. All he could do was stop and stare as a giant foot descended on his miniature body. A combination of the things Luffy had been covered in over the day made him stick to her foot easily. Luffy didn't know what to do. He just lay there thinking 'So close.'