I'm getting erections and some white fluid when having sensual intimate thoughts

I am a 16 yr old boy.... I have a question.... I haven't masturbated till yet .... Haven't watched porn but yah i know everything about it.... My problem is that .... At night while sleeping when some sensual intimate thoughts(You know what i mean to say) strike my dream .... My Penis gets erect and when that thought processes further a whitish-transparent sticky fluid comes out of my penis.... I AM WORRIED THAT WHAT'S HAPPENING WITH ME....IT WILL BE A HUGE HELP IF U CAN HELP ME.....WHAT IS IT? AND WHY DOES IT COME OUT? IS IT HARMFUL OR NORMAL? PLEASE REPLY SOON.... WAITING FOR UR REPLY .... HELP ME OUT WITH THIS.... ND YAH TELL ME IF ITS A BIG PROBLEM AND I NEED SOME STRICT ACTIONS AGAINST IT....I HAVEN'T TOLD MY PARENTS ABOUT IT TILL NOW.... YOU KNOW THAT PARENTS HAVE SO MANY RESPONSIBILITIES ON THEIR HEAD ... SO DON'T WANT TO GIVE THEM A PROBLEM BECAUSE OF ME.... PLEASE TELL ME ABOUT IT.... ND YAH IS IT HARMFUL OR NORMAL? DO REPLY .... WAITING FOR UR HELP FRIENDS....