I found metamucil helped last time. I took the tablets rather than the drink.
I didnt' have a really bad problem with constipation, nor the feeling of any prolapse, but I found metamucil helped, especially when I started taking iron towards the end of the pg to get my blood count up.

A warm drink certainly stimulates the bowel - just ask my DS. He has his cup of warm milk after a shower at night, and GUARANTEED he dirties his nappy LOL. Works for me sometimes too

Hope you find some relief soon!