CUPCAKE-ILICIOUS: Golden Vanilla Cupcakes with Lemon Zest Buttercream Frosting and Blueberry

I have been experimenting with Cupcakes more lately as I am getting ready for the big day (the wedding) when I actually have to make 100 some odd Chumpcake ones. I think I have nailed the cupcake making and the icings I have made are super awesome: peanut butter frosting, regular butercream. A couple of days ago I tried a new Golden Vanilla cupcake recipe from Cupcakes Takeover the World. Delicious!!! I also fudged a delicious lemony icing and added a blueberry on top for a little personality. They look good but I am still trying to nail a really peaky type cupcake icing that isn't melty. If y'all have any suggestions on the type of piping bag I should use and even a recipe that I could use to attain this: