Again playing with the same friend, Here I choose a different alternative.
In this hand I have decided to fill my blind, to try to show a wider range. Probably the best is a standard opening, but I was tempted with the passive idea, because I was going to have position in this hand. Against a standard opponent I suppose I am destroyed on the river.
1) What hands do we expect to make these bet sizes?
2) As played does it make sense to bluff OTR?

Hand: https://www.cardschat.com/replayer/3qTfYJa

Greetings.

Preflop
I am by no means a heads-up specialist, but my thinking is, that SB limping is more of a tournament strategy, when stacks are short, and there is a small ante as well. 100BB deep and without ante I think, its better to raise small or fold our entire range, and any AX would for sure be a raise.

Flop
I am fine with checking back, since you missed and have some showdown value.

Turn
There are many draws, he could be taking a stab with, so I think, you have to defend with A high even without a kicker.

River
Its a little light to call down with A high no kicker, but you have some things in your favour here. You dont block the busted draws, and he would probably raise most of his AX hands preflop. So calling with your particular hand is probably better than calling with for instance 54 of diamonds, which would be nominally stronger but block some of his natural bluffs.

I only like the limp play here if we are going against a villain who is never folding pre. If they are the type of player that heads up you would have to go to 3.5x or larger to get folds then I dont mind limping but if they will fold to some slightly larger than min raises I would lean towards raising pre.

I like betting the flop here since I would want to take control of the hand now and use the chips I "saved" from not raising pre here. I look at it like I am using my bluff here instead of pre flop and it is probably more effective here than it would be pre. Betting here also might dictate villains turn play and if they are not a donk bettor than betting here will get us all the to river if we want it to. Plus betting here might get some folds against random hands that we are beating but want to protect our equity against. The check is fine and by no means bad but I do feel betting is better there.

Since the villain is hard to range here other than we think they are not pair heavy but random card heavy, the 6 could easily hit them or it could be a blank. No way of knowing. I am not sure as played what I would be doing here. I tend to lean fold even though that is weak and in heads up you have to call much more often but I feel like I am getting double barreled on no matter what the river card would be. If I am not prepared right now to call down with ace high not improving then I would fold here at least most of the time and of course during heads up sometimes mix in the calls where I am calling down. I dont feel though it is a good play to call this turn and then fold the river. If you call the turn then you should be calling most river bet sizings as you did in this hand.