A couple of possibilities here. Very often when you run a razor down a strop it will exhibit draw which is a pulling sensation and usually means the razor is in pretty sharp condition. Usually you get that with a plain strop. With a pasted strop sometimes the paste on it causes some friction with the blade which can feel like pulling also. You didn't say what kind of razor you have or what the edge looks like so its hard to tell you much more. If the edge is in good shape and close to shave ready those pasted strops should be all you need but if its not then it will likely need to be honed on a stone. Tell us more about the razor and who honed it for you or what you did to sharpen it.