Ichiru teases Getsuro a lot, because he fell in love with him the first time they met. Since Getsuro said he can call him Ro-kun, Ichiru believes for him to be just another servant (though he is the firstborn child for the moon -> fiance for the firstborn from the moon). Ro-kun teases him back by not correcting his misconception since he believes that Ichiru could be more serious. Also, he believes Ichiru wont be happy to find out he´ll have to settle with a male.