i can! when i travel with my best female fren, she make it very
clear that she will kick me if i try to do something funny to
her...so kinda enforced, not say i very 'xin ru zhi shui' or that i
top student for moral-education...
but she suay suay wake up earlier than me on one day and see my
didi stand up ...i wearing boxers to sleep and cover with blanket,
normally no kick blanket off one, but that day accident
lah...somemore most of time i wake up earlier one to make travel
plans...that day too tired...
i know it cos when i wake up she say "can wear more when u sleep
next time, u got biological response just now... u wear boxer only,
i can see your erection just now, show off ah? " then walk away...
very fierce. 
anyway, sometimes travel with just one platonic female companion
not so fun...also why sleep next to opposite sex bestfriend? got
all the privacy and scenery in the world, but cannot cuddle and do
what we biologically programmed to do!!!
better to be with 4-6 good friends or sleep next to gf.
