We have been doing the same but for poos our daughter will stop feeding, or start/stop, not really suck and do a fart or two.
For wees it is a bit harder. we usually catch them on timing, but a look towards me and a little grizzle is a sign for us.
I have EC'd a couple kids and here are some of the signs I have seen around that age:
-A sudden stop in what they are looking at and looking up at me with a 'something is happening' look
-A sudden faraway look in their eyes like they are concentrating on something
-Especially in a sling--a calmness that is suddenly interrupted by squirming and seeming uncomfortableness
-Sudden crying or 'complaining' while in a car seat
-Of course, gassiness!
-Red face and/or pushing
-If diaper free and a boy, a wee wee 'at attention' ! Also, the 'pouch' contracting
-Sometimes they can start to sign at the age too if I remember correctly. Some type of simplified 'potty' sign language sign
EC so easy with ecaPants!! ~the flip down, drop front, little learning pants
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