Ch. 1-3: Lambert, the new strongman, joined the circus for alluring, but socially inept beast tamer Ulvano. Lambert want to perform with him, but just being around Ulvano makes him hard.
Ch. 4-5: After visiting the circus, famous painter twins Stephan and Silvio become taken with circus clown Tino and force him to be their nude model
Ch. 6: Ringleader Gill is concerned about the circus's finances, but refuses to rely of the masochist owner Roland for help.
Itoshi No Mitsuyoku Circus