Tummy time help

Je

Hoping for some tips! My son will be 4 months this week and he still isn’t really putting much if any weight in his arms during tummy time. He doesn’t love tummy time, but he doesn’t hate it either and he usually does about 45-60 minutes a day. He can lift his head and hold it no problem, though it’s sometimes hard to get him motivated enough to do it. He rolled over once at 12 weeks, but it must have been pure luck because he hasn’t done it again since.

When I put him on his tummy he will bring his hands above his shoulders but out to the sides. If I prop him up with his arms he’ll stay for a few seconds and then splay his arms out again, or just rest his head on them and suck his hands. I tried putting a rolled up towel under him but he just does the same things.

I’ve included a couple of pictures with the rolled up towel to show what I mean. Any tips?