Personalized Stays At My Birthday Party Infant Romper. Funny birthday Infant Romper - White with Las Vegas parody, party hat and balloons, says WHAT HAPPENS AT MY BIRTHDAY PARTY STAYS AT MY BIRTHDAY PARTY! Meet your new favorite outfit! Keep dressing simple with this one piece, lap shoulder t-romper. Super soft and perfect for baby's sensitive skin. 5.5 oz. 100% combed ringspun cotton premium jersey (CVC Colors are 60/40; Heather is 90/10 combed ringspun cotton/polyester)