I just wanted to tell y'all what has worked for me in the past when we find ourselves caught between the proverbial "rock and a hard place". So your sitting on the throne and your constipated, what should you do? Of course straining is a no-no, but how else are you going to pass those "calcified baked potatoes" aka hard stools.
You know that many times our constipation just need to get past the first "deliverance" of our Bm then the rest coming out is much better. So, to get the first part out I would reach down there and gently pull my butt cheek open and then I would without closing the sphincter muscle, push my butt cheek together again.
This action will snip off the first part of the rock hard bm giving the next section a much easier chance. I have done this several times before and it seems to always help. With or without fissures I have done this successfully. Try not to close your sphincter muscles as your sitting there as this only tends to push your bm back up a little. Try to get your hand as close to the opening of your anus as you can before you give it a gentle tug.
All your trying to do is to start up that stuck bm again so even a message like motion with your hand next to the stuck bm can help it come out. Pushing the side of the anus opening in a upward movement right next to the bm that is trying to come out also helps get that "movement" going.
I hope I've explained this to your understanding and you see the picture. Sometimes too I will sit down, realize I'm constipated, then I would get back up and apply the vaseline. Still with all the vaseline, hard stools will still make you strain, so that hand technique will also come in handy here.
This has saved me many a times from straining and pushing too much which of course is like watering and giving sunshine to a growing fissure fledgling. And I know I have averted a few "fish" with this technique.
Please do feel free to add your own tips and tricks for all to this or your own threads.
Hope this helps & good Luck