Oliver was fixed at 5 1/2 months and never lifts his leg in the house (besides inside the litterbox...) I think it's so funny because even though he hikes his leg his peepee still goes straight down because he's so small! It cracks me up that he tries to be a big tough dog (outside when he marks on trees) and his peepee doesn't even hit the tree! hehe
Goodluck!