There's no reason pajamas can't be sexy sleepwear. Whether sold as a set--top and bottoms--or as separates, there are pajamas on the market that are every bit as hot as the sexiest of gowns. Look for animal prints or short pajamas in sexy fabrics--like satin or sheer.
If you prefer separates, try little camisole tops with matching shortie bottoms. Even a classic tailored pajama can be sexy if it's see-through and trimmed in sensuous fabrics, like satin.