Ball Behaviour

[scalawag]

Both of my balls displays this behaviour. They both will lay there flat with maybe the upper fifth of their body almost straight up, motionless for what sometimes 10 - 20 minutes. Is this a breeding type behaviour, are they tasting for pheremones? It's usually about this time of year. One is a male and the other was probed by a friend, I think its a female(a rescue), kinda on the light side, I'm trying to fatten her up but she's been off-feed for about a month. Temps are fine and stable, UTH, hides, humidity. I believe all my husbandry is fine, much of which I trust from this site. So is this usual behaviour? The male I've had 3 yrs and he does this every year. Thanks.
In Mouth We Trust...