SP without even trying!

Ok, so ive been trying to WILD on and off this whole year and would sometimes lay in my bed for 2 hours without even getting any sign of SP so i sort of gave up again. Last night when i was lying in my bed i was simply letting my thoughts do whatever they want because i had no intention of doing any kind of WBTB when i would wake up later. I was just watching my imagination for about only 10 minutes and then everything suddenly felt heavy, i was a bit suprised that i was actually having SP for the first time but i remained calm, then it was harder to breathe and my breathing rate increased, the sound of silence in my ears grew louder, and i was having light vibrations. I still tried to remain calm best i could by forcing random thoughts in my head and then my eyelids started twitching like crazy, it didnt make any sense at all and i kept trying to keep my eyelids still but ended up making all the SP sensations cease. I layed there for 5 more minutes and got SP again and another 5 minutes later i did it again! Now ive finally figured out how to reach SP so easily without the need for concentrating on something that would keep my body awake during my attempts at WILD. This brings me new hope in finally acheiving WILD. Later that night i had a FA where i got SP but i failed and got out of bed (Damnit i should have done a reality check). My question is, what do i do after i reach SP?, i didnt see any imagery and i tried imagining some but it didnt work, and how do you remain calm while in SP?