Gloucestershire built a commanding lead over Glamorgan on day two as they reached 284-6 - a lead of 147.
Skipper Michael Hogan took the only wicket of the day for the Welsh county as Jack Taylor and Ben Charlesworth built an unbeaten 143 run partnership.
Timm van der Gugten was the pick of the bowlers, taking 2/54 from 28 overs and believes the pair have shown Glamorgan's batsmen how to bat in the second innings.
"Charlesworth and Taylor batted really well and showed us how to play on this wicket- they kept out the straight ones and latched onto anything with any width or over-pitched," said Timm van der Gugten.
"It has been frustrating for us lately, but we've got another innings for the batters to have a chance, there's no demons in the wicket so if we apply ourselves like those two did, then the batters can spend some time in the middle and we can build a lead."