Try one of the multi-story carparks at Blks 285E , Toh Guan
Rd.
During the day, if you drive up the upper stories, there's zero
cars around. Some more, if you face the direction of IMM, there's a
very big green field. So there's no flats around where ppl with
prying eyes can see what you're doing.
I've been there once wif my gf lar....made out there. But too bad
she didn't want to bonk coz it was too bright.