webmethod enable session

[WebMethod(EnableSession = true)]
        public static string AddBookmark(string inputText)
        {
            string[] ip = inputText.Split('~');
            if (ip[1] == "XXX")
            {
                return string.Format("Error");
            }
            else
            {
                /* enter data into db */
                Url_BLL obj = new Url_BLL();
                int i = obj.Add_Update_Url_BLL(ip[1].ToString(), ip[1].ToString(), ip[1].ToString(), ip[1].ToString(), ip[1].ToString(), Session["UserEmail"].ToString());
                /* enter data into db end */
                if(i==-1)
                    return string.Format("{0}", "Added!");
                else
                    return string.Format("{0}", "Sorry Error!");
            }
        }

Error	36	An object reference is required for the non-static field, method, or property 'System.Web.UI.Page.Session.get'