We have a boy and a girl. They were carefully potty trained right away. I bought a 4x4' cage they had a bed, pee pee pad, food and water, and toys in their cage. They still sleep in their cage, no pee pee pad needed (now 1 1/2 yoa) Bronx only humped at the appropriate time and never anyone or anything else. I understand it is a trainable offense. Never let them do what you hate (even if it is cute at first, or if you just want to look the other way-dont).
Our big problem with marking came when we bought a different house last sept. The previous owners had chiuauas (sp?) which they raised pups and their dogs peed everywhere (tile floors) He peed everywhere. I am still scrubbing grout with toothbrush and sealing (we have four open rooms downstairs). Still I have little 3 spot pees all over - he pees outside, but he marks in the house like an obsession. We have also had a couple of dog visitors, which make him get worse. (he also peed on one of my husband's friends boot, with him in it
- boy was that embarrasing.)
I felt the same way with yapping. I carefully instructed the family - no matter how cute it is, the dogs are not encouraged to bark. It has worked out fine, they will bark at doorbells and such, but people constantly comment as to how well behaved they are and they thought all small dogs were yappy. Ours arent.