It is your unwritten responsibility to sit perpendicular to the seat and never at an angle while riding a jeepney, especially when said vehicle is currently stopped and accepting passengers. This vehicle is not yours, it belongs to the public. As such, you should never occupy space more than the width of your buttocks by sitting at an obtuse angle. This is especially true if you are planning to or might fall asleep. Honestly, I cannot understand why some people find it more comfortable to have their sides supported over their spines.
In relation to this, please do not open your legs more than your hip requires. The comfort factor might be agreeable here, especially as a man, but, again, out of respect and courtesy, please avoid doing so.
Remember that we are all in this together. The faster you orient yourself to accommodate others, the quicker the journey for all of us.
Your Fellow Jeepney Passenger,