We talk there about a really small onahole that will fit into any pocket.
Just using a good amount of spit or hot water will do the job, for outside masturbation.
The structure may be strange at first, but I quite liked it.
Way worth the price, as I already said.
This one has just the right structure inside, a simple and delicate twist and provides a rather decent stimulation to your head. The stimulation could be strong for some, as it was for me, but this is indeed better than the Chu! 4 in some ways.