Does the suck swallow slow to almost nothing? Done eating.
Does the suck pressure change from, "OMG he going to remove my nipple" to anything else? Comfort nursing.
If you are comfortable with it, you may consider a paci. If you are not comfortable with the paci- then he is going to use your teat to soothe himself. Pacis simply replace the breast in regards to the self soothing suck.