"If we get married at home we would love our dog Ted to carry the rings up the aisle on his back," the 28-year-old said.
"It would be really cute. I don't know if that will be possible but he'll definitely be present on the day if we have the wedding in Ireland."
Wes and Rosanna recently got engaged during a family holiday in Mauritius. And Rosanna says he's a changed man since he proposed.
"I've noticed that he started being much more attentive," the former Miss World said.
"He was making the bed this morning and he went off and posted my mail for me. He's doing a lot of grocery shopping," she mused.
"We feel closer since the engagement and that we have to look after each other more."
But Rosanna says she's still getting used to being engaged.
"We do sometimes call each other fiance, just to see what it sounds like. But it's feels really odd because we're so used to being boyfriend and girlfriend."
The pair are planning their big day for summer next year and Rosanna says they won't be going down the traditional route.
"I've been to so many traditional and formal weddings where you can predict everything that is happening and I'm not into that. I would like to do something different, something that reflects us."
Wes and Rosanna have yet to pick a location but she says where they say "I do" will determine what her dress will be like.
"What I wear will completely depend on the location. If it was in Ireland then it would be something more traditional. But if it was abroad, I would go shorter or for something a bit more flowy. And I would definitely have the white bikini underneath the dress."