His mouth was taped shut.
Waluigi didn't want to admit the fault of his attraction to Luigi, no, he didn't. Luigi was his rival, and rivals weren't supposed to love each other.
He had to settle for teasing him, being a bully, just so he wouldn't fall on his knees and beg to be loved back. He had to hang the shorter in a tree by his overall straps, just so he wouldn't smother him in sloppy kisses. He had to act like he wanted Daisy just to keep his cover.
Which caused Waluigi to be a loner. He stayed at home as often as he could, hardly ever went out to even grab a drink. Waluigi didn't want his cover blown.
Even Daisy herself started to come up to his door and ask what's been keeping him in his house all the time.
Every one, except Luigi. Luigi seemed to be thankful that the taller was locked in his house.
Daisy, finally, had to break into Waluigi's house one day just so he'd talk to her face to face. Arms crossed, stern look on her face, she growled the question of why he didn't even come out to tennis matches anymore.
Waluigi just pulled the blanket over his head and muttered his begs to be left alone.
The Princess just ignored him, kept on questioning, even yanked him to his front door and kicked him out of the house onto the lawn. He wanted to go back inside; Waluigi hadn't taken a shower today.
Daisy then knelt down next to him, pressing a kiss to his forehead and asking, "Is this enough to make you come back out?"
Waluigi wished he could kill her and bury her in the desert. "No." He pushed her away and went back inside.
The rest of the week followed with Daisy breaking in, kicking him out of his house, either to the sidewalk, the curb, or the outskirts of the city.
The last day of the week, Luigi saw the situation and ran over, asking what was wrong.
"Mr. Shut-in here," Daisy replied, "Hasn't been out of the house in weeks."
"So what, Daisy? Leave him alone."
"Please." Waluigi begged, "Even Luigi wants me inside!"
"Maybe if Luigi went ahead and told you." Daisy smirked, "You just might stay locked in together."
Waluigi saw Luigi blush, kicking the ground. Daisy punched his shoulder, "Go ahead, Weegee."
Waluigi just sat on the ground, brushing dirt off the side of his face.
Luigi looked up and said, "C-can we go out, sometime, Waluigi?"
Dream come true. He didn't even have to open his mouth.