You can make a swirl on a cupcake without having a tip. You can do this by putting you frosting, icing sugar cream of whip cream in one corner of a plastic bag. Proceed to make a small hole on that corner and as you press on it, make sure to swirl your hand sp that the topping will come out swirly.
Yep!!! Fill a plastic bag full of your frosting, and cut a hole at the bottom. (Depending on how thin or thick you want your frosting to look!) Then Just do the same thing you would do with a professional tip!!! Hope this helped!!!! :D